Fix missing variable name in exception handler.

TEST=should stop throwing an exception when retrying for git checkouts
BUG=none

Review URL: http://codereview.chromium.org/2002015

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@46960 0039d316-1c4b-4281-b951-d872f2087c98

gclient_scm.py

@@ -260,7 +260,7 @@ class GitWrapper(SCMWrapper):
             self.checkout_path,
             print_error=False)
         break
-      except gclient_utils.CheckCallError:
+      except gclient_utils.CheckCallError, e:
         # Hackish but at that point, git is known to work so just checking for
         # 502 in stderr should be fine.
         if '502' in e.stderr: