Repair reopen topic action

Followup to javacsript post/topic moderation patch (763917) finishes
the aliasing of specific moderation types like unhide and reopen
to restore.

Bug: 68172
Change-Id: I3ac07836997d875ceddc45407e676879f172e069
(cherry picked from commit d8fee1da199c244207a3b81fe7a5f7e74f9e9e51)
Restore previous behavior of Reference::makeTitle

Prior to the patch that enabled topic namespaces (02ca2823) this
method returned null on failure, re-instate that for invalid
input exceptions but not for cross-wiki or other exception types.

Bug: 68225
Change-Id: I05d73f2f5fb5b52452b313411cff99eb8440d234
(cherry picked from commit d9fde87fd64c324bde0e08677b929533f18a2e0f)
Merge "Repair reopen topic action" into wmf/1.24wmf14