Distinguish branches by more than case in tests.

The renaming without config test changed a branch from q to Q, which
fails on non-case sensitive file systems.  Change the test to use q
and q2.

Signed-off-by: Junio C Hamano <junkio@cox.net>

t/t3200-branch.sh

@@ -85,9 +85,9 @@ test_expect_failure \
 
 mv .git/config .git/config-saved
 
-test_expect_success 'git branch -m q Q without config should succeed' '
-	git-branch -m q Q &&
-	git-branch -m Q q
+test_expect_success 'git branch -m q q2 without config should succeed' '
+	git-branch -m q q2 &&
+	git-branch -m q2 q
 '
 
 mv .git/config-saved .git/config