py3: conditionalize _winreg import _winreg module is renamed to winreg in python 3. Added the conditionalize statements in the respective file because adding this in pycompat will result in pycompat throwing error as this is a windows registry module and we have buildbots and most of the contributors on linux.

py3: conditionalize the raise statement raise E,V,T is not acceptable in Python 3, thats is conditionalized. Moreover this will result in syntax error so we have to use exec() to execute this. Related PEP- https://www.python.org/dev/peps/pep-3109/#id14 My implementation is motivated from the six implementation except they are defining a new function exec_() to prevent adding an extra frame AFAIK :) https://bitbucket.org/gutworth/six/src/ca4580a5a648/six.py#six.py-680

match: added matchessubrepo method to matcher Previously there were three local implementations of this function in cmdutil.files, cmdutil.remove and scmutil.addremove.

changegroup: move branch cache debug message to proper location Before, we logged about performing a branch cache update when we weren't actually doing it. Fix that.

journal: take wlock for writting the 'shared' file As we did for the shared extension itself, we add some locking around the write of the 'shared' file.

debugbuilddag: take wlock to cover '.hg/localtags' This debug command can write local tags. local tags are in the .hg directory and should be covered by the 'wlock'. This is now covered.

fakemergerecord: take wlock to write the merge state The merge state is supposed to be covered by the wlock. We fix the test extensions to comply to that.