pull: abort pull --update if config requires destination (issue5528)

tests: move update requiredest test to own test file More tests for this flag are coming in upcoming patches.

py3: add pycompat.unicode and add it to importer On python 3, builtins.unicode does not exist.

py3: add a bytes version of urllib.parse.urlencode() to pycompat.py urllib.parse.urlencode() returns unicodes on Python 3. This commit adds a method which will take its output and encode it to bytes so that we can use bytes consistently.

py3: replace str() with bytes()

metadataonlyctx: replace "changeset()[0]" to "manifestnode()" As Yuya pointed out [1], "changeset()[0]" could be simplified to "manifestnode()". I didn't notice that method earlier. It should definitely be used - it's easier to read, and faster. [1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-March/095716.html

test-check-pylint: match its output "pylint --version" shows: pylint 2.0.0, astroid 1.5.0 Python 2.7.13 (default, Dec 21 2016, 07:16:46) [GCC 6.2.1 20160830] I got "Your code has been rated at 10.00/10" every time and didn't know how to turn it off. Therefore the fix.

test-flagprocessor: remove unnecessary greps The "2>&1 | egrep ..." code is used for removing uninteresting parts from tracebacks. Now the test does not dump tracebacks, they can be removed.

bundlerepo: use raw revision in revdiff() This is similar to "revlog: use raw revisions in revdiff". revdiff() generates raw text used in revlog directly. This makes test-flagprocessor.t happy.

bundlerepo: fix raw handling in revision() Similar to fixes in revlog.py, this patch uses "rawtext" to explicitly label contents expected to be raw, and makes sure content stored in _cache is raw text. Now test-flagprocessor.t points us to another issue.