t/{t5541,lib-httpd}: replace problematic '!()' notation with test_must_fail

The '!()' notation is interpreted as a pattern-list on Ksh.  The Ksh man
page describe it as follows:

   !(pattern-list)
      Matches anything except one of the given patterns.

Ksh performs a file glob using the pattern-list and then tries to execute
the first file in the list.  If a space is added between the '!' and the
open parens, then Ksh will not interpret it as a pattern list, but in this
case, it is preferred to use test_must_fail, so lets do so.
Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/lib-httpd.sh

@@ -145,7 +145,7 @@ test_http_push_nonff() {
 		echo "changed" > path2 &&
 		git commit -a -m path2 --amend &&
 
-		!(git push -v origin >output 2>&1) &&
+		test_must_fail git push -v origin >output 2>&1 &&
 		(cd "$REMOTE_REPO" &&
 		 test $HEAD = $(git rev-parse --verify HEAD))
 	'

t/t5541-http-push.sh

@@ -128,7 +128,7 @@ test_expect_success 'push fails for non-fast-forward refs unmatched by remote he
 
 	# push master too; this ensures there is at least one '"'push'"' command to
 	# the remote helper and triggers interaction with the helper.
-	!(git push -v origin +master master:retsam >output 2>&1) &&
+	test_must_fail git push -v origin +master master:retsam >output 2>&1 &&
 
 	grep "^ + [a-f0-9]*\.\.\.[a-f0-9]* *master -> master (forced update)$" output &&
 	grep "^ ! \[rejected\] *master -> retsam (non-fast-forward)$" output &&