Dead code removal: #if 0 conf, dso, pqueue, threads

Mostly, but not completely, debugging print statements.
Some old logic kept for internal documentation reasons, perhaps.

Reviewed-by: Richard Levitte <levitte@openssl.org>

crypto/pqueue/pqueue.c

@@ -179,13 +179,6 @@ pitem *pqueue_find(pqueue_s *pq, unsigned char *prio64be)
     if (!found)
         return NULL;
 
-#if 0                           /* find works in peek mode */
-    if (prev == NULL)
-        pq->items = next->next;
-    else
-        prev->next = next->next;
-#endif
-
     return found;
 }