Fix: Authors unable to comment on posts they authored when under owned by others…

Fix: Authors unable to comment on posts they authored when under owned by others in certain circumstances.

In certain circumstances, perm_is_allowed() was being referenced even if the post author was commenting. The behavior - as per a conversation with Mike - is that authors should always be allowed to comment on their own authored posts, even on forums where the forum channel is the "owner" of the post.

This patch fixes the problem both for authors attempting to comment on the wall of the channel where their authored post appears - as well as for comments by the author of the original post when it is delivered by the network because it was posted on another page.