bundlerepo: apply phase data stored in the bundle instead of assuming `draft` The phase information contained in the changegroup part and the explicit `phase-heads` part are now taken in account. Initial changes and test by Matt Harbison, code rework by Pierre-Yves David.

bundlerepo: handle changegroup induced phase movement in the associated method These movement comes from handling the changegroup part, so we keeps the code grouped. This will be important when handling more part (and more changegroup part in the future) This induce a small code duplication, but it does not looks terrible.

bundlerepo: move most attribute declaration earlier in __init__ The expected attribute are clearer this way. The bundle handling code is responsible for setting most of it.

bundlerepo: move the handling of bundl1 in its own method This should make the overall flow simpler to follow.