Merge branch 'bc/http-push-flagsfix'

The code to push changes over "dumb" HTTP had a bad interaction
with the commit reachability code due to incorrect allocation of
object flag bits, which has been corrected.

* bc/http-push-flagsfix:
  http-push: ensure unforced pushes fail when data would be lost

diff --cc http-push.c
Simple merge

diff --cc object.h
Simple merge