Skip over paladin patches in commit messages.
Skip over paladin patches in commit messages.

Right now, paladin builds up its commit message before rebasing,
resulting in user commit messages sneaking in to paladin commits. We
should rebase prior to building up the commit message, as this will
ensure that already-committed revs don't show up in the automatically
generated message.

BUG=chromium-os:26558
TEST=Trybot run.

Change-Id: I9768cf61bb4599cc851bf66d26c5373779615a68
Reviewed-on: https://gerrit.chromium.org/gerrit/16485
Reviewed-by: Chris Sosa <959d3d631fb6f17f1b07f751372041a1edb210d1@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Commit-Ready: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>

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