! Permission checks weren't always done properly when replying to topics...

... (fixes #1179)

This fixes both the original issue and another one that was discovered while investigating the first (a user who didn't have either permission to reply to their own topics but did have permission to post unapproved replies to any topics was unable to reply as well).

Signed-off-by: Michael Eshom <oldiesmann@oldiesmann.us>