Add codereview.settings to depot_tools.

I'm doing this while trying to figure out the best way to make git-cl
auto-configure itself on first use, including automatic presubmit scripts hook
setup.

TEST=none
BUG=none

Review URL: http://codereview.chromium.org/559002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@37709 0039d316-1c4b-4281-b951-d872f2087c98

codereview.settings

+# This file is used by gcl to get repository specific information.
+CODE_REVIEW_SERVER: codereview.chromium.org
+CC_LIST: chromium-reviews@chromium.org
+VIEW_VC: http://src.chromium.org/viewvc/chrome?view=rev&revision=
+GITCL_PREUPLOAD: http://src.chromium.org/viewvc/chrome/trunk/tools/depot_tools/git-cl-upload-hook?revision=HEAD
+GITCL_PREDCOMMIT: http://src.chromium.org/viewvc/chrome/trunk/tools/depot_tools/git-cl-upload-hook?revision=HEAD