Make git-try behave like calling trychange.py directly.

That fixes the common usage "git-try <branch>" so the diff is generated against
a branch.

BUG=46697
TEST=none

Review URL: http://codereview.chromium.org/3433011

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@59550 0039d316-1c4b-4281-b951-d872f2087c98

git-try

@@ -38,7 +38,7 @@ def GetRietveldServerUrl():
 
 
 if __name__ == '__main__':
-  args = sys.argv[:]
+  args = sys.argv[1:]
   patchset = GetRietveldPatchsetNumber()
   if patchset:
     args.extend([