shell portability: no "export VAR=VAL"

It is more portable to say "VAR=VAL && export VAR" instead.

Noticed by Ævar.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-am.sh

@@ -137,7 +137,7 @@ It does not apply to blobs recorded in its index."
     export GITHEAD_$his_tree
     if test -n "$GIT_QUIET"
     then
-	    export GIT_MERGE_VERBOSITY=0
+	    GIT_MERGE_VERBOSITY=0 && export GIT_MERGE_VERBOSITY
     fi
     git-merge-recursive $orig_tree -- HEAD $his_tree || {
 	    git rerere $allow_rerere_autoupdate

git-rebase.sh

@@ -111,7 +111,7 @@ call_merge () {
 	export GITHEAD_$cmt GITHEAD_$hd
 	if test -n "$GIT_QUIET"
 	then
-		export GIT_MERGE_VERBOSITY=1
+		GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
 	fi
 	eval 'git-merge-$strategy' $strategy_opts '"$cmt^" -- "$hd" "$cmt"'
 	rv=$?

git-stash.sh

@@ -373,7 +373,7 @@ apply_stash () {
 
 	if test -n "$GIT_QUIET"
 	then
-		export GIT_MERGE_VERBOSITY=0
+		GIT_MERGE_VERBOSITY=0 && export GIT_MERGE_VERBOSITY
 	fi
 	if git merge-recursive $b_tree -- $c_tree $w_tree
 	then

t/t1509-root-worktree.sh

@@ -134,8 +134,8 @@ cat >ls.expected <<EOF
 100644 $ONE_SHA1 0	me
 EOF
 
-export GIT_DIR="$TRASH_DIRECTORY/.git"
-export GIT_WORK_TREE=/
+GIT_DIR="$TRASH_DIRECTORY/.git" && export GIT_DIR
+GIT_WORK_TREE=/ && export GIT_WORK_TREE
 
 test_vars 'abs gitdir, root' "$GIT_DIR" "/" ""
 test_foobar_root
@@ -154,24 +154,24 @@ say "GIT_DIR relative, GIT_WORK_TREE set"
 
 test_expect_success 'go to /' 'cd /'
 
-export GIT_DIR="$(echo $TRASH_DIRECTORY|sed 's,^/,,')/.git"
-export GIT_WORK_TREE=/
+GIT_DIR="$(echo $TRASH_DIRECTORY|sed 's,^/,,')/.git" && export GIT_DIR
+GIT_WORK_TREE=/ && export GIT_WORK_TREE
 
 test_vars 'rel gitdir, root' "$GIT_DIR" "/" ""
 test_foobar_root
 
 test_expect_success 'go to /foo' 'cd /foo'
 
-export GIT_DIR="../$TRASH_DIRECTORY/.git"
-export GIT_WORK_TREE=/
+GIT_DIR="../$TRASH_DIRECTORY/.git" && export GIT_DIR
+GIT_WORK_TREE=/ && export GIT_WORK_TREE
 
 test_vars 'rel gitdir, foo' "$TRASH_DIRECTORY/.git" "/" "foo/"
 test_foobar_foo
 
 test_expect_success 'go to /foo/bar' 'cd /foo/bar'
 
-export GIT_DIR="../../$TRASH_DIRECTORY/.git"
-export GIT_WORK_TREE=/
+GIT_DIR="../../$TRASH_DIRECTORY/.git" && export GIT_DIR
+GIT_WORK_TREE=/ && export GIT_WORK_TREE
 
 test_vars 'rel gitdir, foo/bar' "$TRASH_DIRECTORY/.git" "/" "foo/bar/"
 test_foobar_foobar
@@ -180,24 +180,24 @@ say "GIT_DIR relative, GIT_WORK_TREE relative"
 
 test_expect_success 'go to /' 'cd /'
 
-export GIT_DIR="$(echo $TRASH_DIRECTORY|sed 's,^/,,')/.git"
-export GIT_WORK_TREE=.
+GIT_DIR="$(echo $TRASH_DIRECTORY|sed 's,^/,,')/.git" && export GIT_DIR
+GIT_WORK_TREE=. && export GIT_WORK_TREE
 
 test_vars 'rel gitdir, root' "$GIT_DIR" "/" ""
 test_foobar_root
 
 test_expect_success 'go to /' 'cd /foo'
 
-export GIT_DIR="../$TRASH_DIRECTORY/.git"
-export GIT_WORK_TREE=..
+GIT_DIR="../$TRASH_DIRECTORY/.git" && export GIT_DIR
+GIT_WORK_TREE=.. && export GIT_WORK_TREE
 
 test_vars 'rel gitdir, foo' "$TRASH_DIRECTORY/.git" "/" "foo/"
 test_foobar_foo
 
 test_expect_success 'go to /foo/bar' 'cd /foo/bar'
 
-export GIT_DIR="../../$TRASH_DIRECTORY/.git"
-export GIT_WORK_TREE=../..
+GIT_DIR="../../$TRASH_DIRECTORY/.git" && export GIT_DIR
+GIT_WORK_TREE=../.. && export GIT_WORK_TREE
 
 test_vars 'rel gitdir, foo/bar' "$TRASH_DIRECTORY/.git" "/" "foo/bar/"
 test_foobar_foobar

t/t5560-http-backend-noserver.sh

@@ -14,7 +14,7 @@ run_backend() {
 }
 
 GET() {
-	export REQUEST_METHOD="GET" &&
+	REQUEST_METHOD="GET" && export REQUEST_METHOD &&
 	run_backend "/repo.git/$1" &&
 	unset REQUEST_METHOD &&
 	if ! grep "Status" act.out >act
@@ -26,8 +26,8 @@ GET() {
 }
 
 POST() {
-	export REQUEST_METHOD="POST" &&
-	export CONTENT_TYPE="application/x-$1-request" &&
+	REQUEST_METHOD="POST" && export REQUEST_METHOD &&
+	CONTENT_TYPE="application/x-$1-request" && export CONTENT_TYPE &&
 	run_backend "/repo.git/$1" "$2" &&
 	unset REQUEST_METHOD &&
 	unset CONTENT_TYPE &&
@@ -46,7 +46,7 @@ log_div() {
 . "$TEST_DIRECTORY"/t556x_common
 
 expect_aliased() {
-	export REQUEST_METHOD="GET" &&
+	REQUEST_METHOD="GET" && export REQUEST_METHOD &&
 	if test $1 = 0; then
 		run_backend "$2"
 	else

t/t556x_common

@@ -50,7 +50,7 @@ get_static_files() {
 }
 
 SMART=smart
-export GIT_HTTP_EXPORT_ALL=1
+GIT_HTTP_EXPORT_ALL=1 && export GIT_HTTP_EXPORT_ALL
 test_expect_success 'direct refs/heads/master not found' '
 	log_div "refs/heads/master"
 	GET refs/heads/master "404 Not Found"
@@ -73,7 +73,7 @@ test_expect_success 'export if git-daemon-export-ok' '
         get_static_files "200 OK"
 '
 SMART=smart
-export GIT_HTTP_EXPORT_ALL=1
+GIT_HTTP_EXPORT_ALL=1 && export GIT_HTTP_EXPORT_ALL
 test_expect_success 'static file if http.getanyfile true is ok' '
 	log_div "getanyfile true"
 	config http.getanyfile true &&