merge: don't grab wlock when merging in memory
I noticed this because we have an internal extension that does an
in-memory rebase while holding only a repo lock, which resulted in a
developer warning about the working copy lock being taken after the
repo lock.
Differential Revision: https://phab.mercurial-scm.org/D8665
# The 9mail to support patchbomb and other email wrappers
[email]
method = /bin/mercurial/9mail