forms: Allow user name and email to be blocked

Fixes a regression in 1.8 where user names and emails submitted via the web
interface would not properly be detected by the filter system for rejection.

References:
http://osticket.com/forum/discussion/75456/v1-8-ticket-filter-for-banning-domain-doesn-t-work
Merge pull request #319 from greezybacon/issue/reject-web-user-emails

forms: Allow user name and email to be blocked

Reviewed-By: Peter Rotich <peter@osticket.com>