merge with -stable

bundlerepo: it was meant to be revdiff() instead of chunk()

patchbomb: fix timezone offset in message date header Use mercurial.util instead of time to set and format dates.

fix for digest auth when using keepalive.py The problem was with python > 2.3 which stores part of the headers in unredirected_hdrs. Furthermore, we simplify the code to use httplib directly. fix issue473