shelve: disallow commit while unshelve is in progress

Before this patch, commit is allowed even while unshelve is in
progress.

In the other hand, "hg unshelve --abort" and "hg unshelve --continue"
check whether parent revisions of the working directory have changed
or not since last "hg unshelve", and abort without clearing state for
unshelve in progress if they have.

This causes that accidental commit makes clearing state for unshelve
difficult in ordinary ways.

This patch disallows commit while unshelve is in progress for
consistency.

hgext/shelve.py

@@ -704,5 +704,6 b' def shelvecmd(ui, repo, *pats, **opts):'
 
 def extsetup(ui):
     cmdutil.unfinishedstates.append(
-        [shelvedstate._filename, False, True, _('unshelve already in progress'),
+        [shelvedstate._filename, False, False,
+         _('unshelve already in progress'),
          _("use 'hg unshelve --continue' or 'hg unshelve --abort'")])

tests/test-shelve.t

@@ -303,6 +303,11 b' attempt to continue'
   $ hg revert -r . a/a
   $ hg resolve -m a/a
 
+  $ hg commit -m 'commit while unshelve in progress'
+  abort: unshelve already in progress
+  (use 'hg unshelve --continue' or 'hg unshelve --abort')
+  [255]
+
   $ hg unshelve -c
   unshelve of 'default' complete