mq: make qrefresh/qfold keep wlock until saving patch status

Because q.refresh() changes nodeid, .hg/patches/status gets invalid until
q.savedirty(). This patch changes mq not to unlock repository of incomplete
state.

hgext/mq.py

@@ -2275,9 +2275,13 b' def refresh(ui, repo, *pats, **opts):'
         # We don't want to lose the patch message if qrefresh fails (issue2062)
         repo.savecommitmessage(message)
     setupheaderopts(ui, opts)
+    wlock = repo.wlock()
+    try:
     ret = q.refresh(repo, pats, msg=message, **opts)
     q.savedirty()
     return ret
+    finally:
+        wlock.release()
 
 @command("^qdiff",
          commands.diffopts + commands.diffopts2 + commands.walkopts,
@@ -2366,9 +2370,13 b' def fold(ui, repo, *files, **opts):'
         message = ui.edit(message, user or ui.username())
 
     diffopts = q.patchopts(q.diffopts(), *patches)
+    wlock = repo.wlock()
+    try:
     q.refresh(repo, msg=message, git=diffopts.git)
     q.delete(repo, patches, opts)
     q.savedirty()
+    finally:
+        wlock.release()
 
 @command("qgoto",
          [('f', 'force', None, _('overwrite any local changes'))],