hg: update to use vfs functions in shared destination repository
This patch uses destvfs with base as .hg directory in shared destination
repository to update filesystem function with vfs. Some methods are changed to
use vfs functions with destvfs.
branch 'default' HG: bookmark '@' HG: changed mercurial/hg.py
hg: use vfs functions in destination repository with share
In this patch, dstwvfs is added to use vfs functions in working directory of
destination shared repository. Existing filesystem operations are updated
to use vfs functions through dstwvfs.