tests: "cp -a" is a GNUism

These tests just want a bit-for-bit identical copy; they do not need
even -H (there is no symbolic link involved) nor -p (there is no
funny permission or ownership issues involved).

Just use "cp -R" instead.
Signed-off-by: NBen Walton <bdwalton@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t5400-send-pack.sh

@@ -159,7 +159,7 @@ test_expect_success 'receive-pack runs auto-gc in remote repo' '
 	    git commit -a -m "Second commit" &&
 	    git repack
 	) &&
-	cp -a parent child &&
+	cp -R parent child &&
 	(
 	    # Set the child to auto-pack if more than one pack exists
 	    cd child &&

t/t5550-http-fetch.sh

@@ -22,7 +22,7 @@ test_expect_success 'setup repository' '
 '
 
 test_expect_success 'create http-accessible bare repository with loose objects' '
-	cp -a .git "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
+	cp -R .git "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
 	(cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
 	 git config core.bare true &&
 	 mkdir -p hooks &&

t/t5800-remote-helpers.sh

@@ -76,7 +76,7 @@ test_expect_success 'pushing to local repo' '
 # git-remote-testgit, but is too slow to leave in for general use.
 : test_expect_success 'racily pushing to local repo' '
 	test_when_finished "rm -rf server2 localclone2" &&
-	cp -a server server2 &&
+	cp -R server server2 &&
 	git clone "testgit::${PWD}/server2" localclone2 &&
 	(cd localclone2 &&
 	echo content >>file &&