Actually update manifest-versions checkout in RefreshManifestCheckout.
Actually update manifest-versions checkout in RefreshManifestCheckout.

This is a followup to Ic20084f6 to fix an issue where manifest-versions
checkout is not updated and builders pause forever with 'Nothing to
build'.

BUG=chromium-os:27107
TEST=unit tests, run example trybot run.

Change-Id: Ifc69ff91c99fc4174b7fc87ac45b5773a2d2e529
Reviewed-on: https://gerrit.chromium.org/gerrit/17277
Reviewed-by: Brian Harring <fdc2d0a2e2340b623587cee5ea8dff425d1eb1f3@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

chadversary/chromiumos.chromite,zhang0137/chromite,coreos/chromite,coreos/chromite,zhang0137/chromite,coreos/chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,zhang0137/chromite,bpsinc-native/src_third_party_chromite