Handle posts without filenames.

If a post doesn't have a filename (such as because of a post event
changing it), then don't show an empty filename with the post.

templates/post_reply.html

@@ -63,7 +63,7 @@
 					, {{ post.ratio }}
 				{% endif %}
 			{% endif %}
-			{% if config.show_filename %}
+			{% if config.show_filename and post.filename %}
 				, 
 				{% if post.filename|length > config.max_filename_display %}
 					<span title="{{ post.filename }}">{{ post.filename|truncate(config.max_filename_display) }}</span>

templates/post_thread.html

@@ -20,7 +20,7 @@
 				, {{ post.ratio }}
 			{% endif %}
 		{% endif %}
-		{% if config.show_filename %}
+		{% if config.show_filename and post.filename %}
 			, 
 			{% if post.filename|length > config.max_filename_display %}
 				<span title="{{ post.filename }}">{{ post.filename|truncate(config.max_filename_display) }}</span>