Fix imports ordering and remove unused import

hggithub/__init__.py

@@ -5,12 +5,11 @@ Add some usefull command to work with github
 import os
 import os.path as osp
 from shutil import move
+from subprocess import check_output, CalledProcessError, STDOUT
 
-from mercurial import registrar, error
+from mercurial import registrar
 from mercurial.i18n import _
 
-from subprocess import check_output, CalledProcessError, STDOUT
-
 cmdtable = {}
 command = registrar.command(cmdtable)