Update missing option check for ticket editing, since it didn't handle optgroups introduced in r6171.  The previously-selected milestone was incorrectly being listed twice if it still existed, both claiming to be selected.
Update missing option check for ticket editing, since it didn't handle optgroups introduced in r6171.  The previously-selected milestone was incorrectly being listed twice if it still existed, both claiming to be selected.

git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@6713 af82e41b-90c4-0310-8c96-b1721e28e2e2

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