bb.fetch2: SRCREV logic enhancement V2

This is the V2 patch for the SRCREV logic enhancement.

there are several changes compared with the V1:
- rebase it to bb.fetch2 code, and all code are applied to bb.fetch2 instead of bb.fetch
- call urldata_init in FetchData:__init__ according to Richard's suggestion.

this patch has been tested with
- fetch world packages with DISTRO = "poky-bleeding", empty ${DL_DIR}, and null PREMIRROR, MIRROR

Pull URL: git://git.pokylinux.org/poky-contrib.git
Branch: kyu3/srcrev-v2
Browse: http://git.pokylinux.org/cgit.cgi/poky-contrib/log/?h=kyu3/srcrev-v2

Thanks,
Yu Ke <[email protected]>
---

Yu Ke (8):
meta: replace bb.fetch with bb.fetcher.instance bb.fetch2: add urldata_init call for Fetch class bb.fetch2.git.py: add git urldata_init bb.fetch2.svn.py: add urldata_init
bb.fetch2.hg: add hg urldata_init
bb.fetch2.bzr: add bzr urldata_init
Fetcher: break the "SRCREVINACTION" deadlock
Fetcher: only set __BB_DONT_CACHE when SRCREV = "${AUTOREV}"

 bitbake/lib/bb/fetch/__init__.py  |    3 ++
 bitbake/lib/bb/fetch2/__init__.py |   42 +++++++++++++-----------------------
 bitbake/lib/bb/fetch2/bzr.py      |   13 ++++-------
 bitbake/lib/bb/fetch2/git.py      |   17 +++++++--------
 bitbake/lib/bb/fetch2/hg.py       |   24 +++++++++-----------
 bitbake/lib/bb/fetch2/svn.py      |   16 ++++++--------
 meta/conf/bitbake.conf            |    4 +-
 meta/lib/oe/patch.py              |    6 ++--
 8 files changed, 54 insertions(+), 71 deletions(-)