debugcommands: don't shadow the error module

Caught by pytype.

Differential Revision: https://phab.mercurial-scm.org/D7378

mercurial/debugcommands.py

@@ -481,8 +481,8 b' def debugcheckstate(ui, repo):'
             ui.warn(_(b"%s in manifest1, but listed as state %s") % (f, state))
             errors += 1
     if errors:
-        error = _(b".hg/dirstate inconsistent with current parent's manifest")
-        raise error.Abort(error)
+        errstr = _(b".hg/dirstate inconsistent with current parent's manifest")
+        raise error.Abort(errstr)
 
 
 @command(