pg_stat_statements forgot to let previous occupant of hook get control too.

pgss_post_parse_analyze() neglected to pass the call on to any earlier
occupant of the post_parse_analyze_hook.  There are no other users of that
hook in contrib/, and most likely none in the wild either, so this is
probably just a latent bug.  But it's a bug nonetheless, so back-patch
to 9.2 where this code was introduced.

contrib/pg_stat_statements/pg_stat_statements.c

@@ -767,6 +767,9 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query)
 {
 	pgssJumbleState jstate;
 
+	if (prev_post_parse_analyze_hook)
+		prev_post_parse_analyze_hook(pstate, query);
+
 	/* Assert we didn't do this already */
 	Assert(query->queryId == 0);