rebase: remove useless list around repo.revs

As repo.revs already returns a list.

hgext/rebase.py

@@ -193,8 +193,8 b' def rebase(ui, repo, **opts):'
             if not rebaseset:
                 repo.ui.debug('base is ancestor of destination\n')
                 result = None
-            elif not keepf and list(repo.revs('first(children(%ld) - %ld)',
-                                              rebaseset, rebaseset)):
+            elif not keepf and repo.revs('first(children(%ld) - %ld)',
+                                         rebaseset, rebaseset):
                 raise util.Abort(
                     _("can't remove original changesets with"
                       " unrebased descendants"),