Current checkout revision was ignored so it was always acting like if --force was used.
This was overloading the subversion server, creating timeouts, causing a cascading effect that destroyed the tree.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/225022

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@27027 0039d316-1c4b-4281-b951-d872f2087c98