Mailscanner - fixes for pfsense 2.1.x

Mailscanner - fixes for pfsense 2.1.x
This one was supposed to be ok, MAILSCANNER_PREFIX set to the same value you used inside if $pf_version > 2.0 and MAILSCANNER_LOCALBASE set to MAILSCANNER_PREFIX for 2.1 and adding '/local' for 2.2