Readd retries argument and set number of retries in chromite.lib.gs.
Readd retries argument and set number of retries in chromite.lib.gs.

BUG=chromium:231447
TEST=Ran unit tests and verified cros_best_revision --dryrun works.

Change-Id: I29e2c464e84647f5b6a4a857ce0138d704e648d7
Reviewed-on: https://gerrit.chromium.org/gerrit/48133
Tested-by: Robert Flack <96236e735c86b7a403f7cd72f8aa555c4573b3ce@chromium.org>
Reviewed-by: Chris Sosa <959d3d631fb6f17f1b07f751372041a1edb210d1@chromium.org>
Commit-Queue: Robert Flack <96236e735c86b7a403f7cd72f8aa555c4573b3ce@chromium.org>

chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite