Replace some assert(1)s with nonfatal_unreached_once().

These were probably supposed to be assert(0).

src/or/channel.c

@@ -1738,7 +1738,7 @@ channel_get_cell_queue_entry_size(channel_t *chan, cell_queue_entry_t *q)
       rv = get_cell_network_size(chan->wide_circ_ids);
       break;
     default:
-      tor_assert(1);
+      tor_assert_nonfatal_unreached_once();
   }
 
   return rv;

src/or/channeltls.c

@@ -601,7 +601,7 @@ channel_tls_get_remote_descr_method(channel_t *chan, int flags)
         break;
       default:
         /* Something's broken in channel.c */
-        tor_assert(1);
+        tor_assert_nonfatal_unreached_once();
     }
   } else {
     strlcpy(buf, "(No connection)", sizeof(buf));
@@ -670,7 +670,7 @@ channel_tls_is_canonical_method(channel_t *chan, int req)
         break;
       default:
         /* This shouldn't happen; channel.c is broken if it does */
-        tor_assert(1);
+        tor_assert_nonfatal_unreached_once();
     }
   }
   /* else return 0 for tlschan->conn == NULL */