1.0.2dev: further refactor of `grant_perm` and `revoke_perm` 
1.0.2dev: further refactor of `grant_perm` and `revoke_perm` 

 - do a config touch to force reload of perms, as this is less heavy
   handed than a restart
 - make sure that `trac-admin` is only called once



git-svn-id: 50cd48c816abc7a9f40e8e03a4277466cb30a3e4@11764 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac