t3200,t7201: replace '!' with test_must_fail

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3200-branch.sh

@@ -200,7 +200,7 @@ test_expect_success \
 
 test_expect_success \
     'branch from non-branch HEAD w/--track causes failure' \
-    '!(git branch --track my10 HEAD^)'
+    'test_must_fail git branch --track my10 HEAD^'
 
 # Keep this test last, as it changes the current branch
 cat >expect <<EOF

t/t7201-co.sh

@@ -335,6 +335,6 @@ test_expect_success \
     git checkout -b delete-me master &&
     rm .git/refs/heads/delete-me &&
     test refs/heads/delete-me = "$(git symbolic-ref HEAD)" &&
-    !(git checkout --track -b track)'
+    test_must_fail git checkout --track -b track'
 
 test_done