Fix failing test on OSX.

THe `cat ... | wc -l` command on Mac has leading spaces in its output,
and was causing these tests to fail.

I may come up with a better fix when I do a full Bash review after the
0.4.0 release.

Author: ingydotnet

test/branch-rev-list-one-path.t

@@ -31,11 +31,11 @@ is "$(
   "Created branch 'subrepo/bar' and worktree '.git/tmp/subrepo/bar'." \
   "subrepo branch command output is correct"
 
-is "$(
+is $(
   cd $OWNER/foo
   git rev-list subrepo/bar | wc -l
-)" \
-  "6" \
+) \
+  6 \
   "We have only created commits for one of the paths"
 
 done_testing

test/branch-rev-list.t

@@ -35,11 +35,11 @@ is "$(
   "Created branch 'subrepo/bar' and worktree '.git/tmp/subrepo/bar'." \
   "subrepo branch command output is correct"
 
-is "$(
+is $(
   cd $OWNER/foo
   git rev-list subrepo/bar | wc -l
-)" \
-  "5" \
+) \
+  5 \
   "We have only created commits for one of the paths"
 
 done_testing