Fix regexp used for enumerating remotes.

R=szager@chromium.org
BUG=413391

Review URL: https://codereview.chromium.org/598153003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@292123 0039d316-1c4b-4281-b951-d872f2087c98

git_rebase_update.py

@@ -44,7 +44,7 @@ def fetch_remotes(branch_tree):
   tag_set = git.tags()
   fetchspec_map = {}
   all_fetchspec_configs = git.run(
-      'config', '--get-regexp', r'remote\..*\.fetch').strip()
+      'config', '--get-regexp', r'^remote\..*\.fetch').strip()
   for fetchspec_config in all_fetchspec_configs.splitlines():
     key, _, fetchspec = fetchspec_config.partition(' ')
     dest_spec = fetchspec.partition(':')[2]