gpg: make sign acquire wlock before processing...
gpg: make sign acquire wlock before processing
Before this patch, "hg sign" of gpg extension executes/evaluates below
without acquisition of wlock.
- repo.dirstate.parents()
- '.hgsigs' not in repo.dirstate
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
To avoid this issue, this patch makes "hg sign" of gpg extension
acquire wlock before processing.
