If we quote as --receive-pack="git receive-pack --reviewer=foo@example.com",
git will try to run "git receive-pack --reviewer=foo@example.com" command
and failed like this

Gerrit Code Review: git receive-pack --reviewer=foo@example.com: not found
fatal: The remote end hung up unexpectedly
Command "git push --receive-pack="git receive-pack --reviewer=foo@example.com" origin HEAD:refs/for/master" failed.

Review URL: http://codereview.chromium.org/9325018

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@120337 0039d316-1c4b-4281-b951-d872f2087c98