need a "contains" option for Owner if restrict_owner is true

[anonymous]

#1439 ([1664]) tied up the "restrict_owner" to control not only the newticket page but also the search page.

However in light of requests to edit or clean-up the userlist (#2351, #1347) - it should be recognised that dropdown for owners of "new tickets" may not be the same as the owners you want to search for.

so we need the "contains, startswith, endswith" options for owner even if the restrict_owner is true.

This does stop those of us using the "query" system from effectively managing our reporters.