BUG/MINOR: peers: Missing initializations after peer session shutdown.

This patch fixes a bug introduced by 045e0d4 commit where it was really a bad
idea to reset the peer applet context before shutting down the underlying
session. This had as side effect to cancel the re-initializations done by
peer_session_release(), especially prevented this function from re-initializing
the current table pointer which is there to force annoucement of stick-table
definitions on when reconnecting. Consequently the peers could send stick-table
update messages without a first stick-table definition message. As this is
forbidden, this leaded the remote peers to close the sessions.
diff --git a/src/peers.c b/src/peers.c
index 10045c6..a210de3 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -2505,7 +2505,6 @@
 								else  {
 									ps->reconnect = tick_add(now_ms, MS_TO_TICKS(50 + random() % 2000));
 									peer_session_forceshutdown(ps->appctx);
-									ps->appctx = NULL;
 								}
 							}
 							else if (tick_is_expired(ps->heartbeat, now_ms)) {
@@ -2513,8 +2512,7 @@
 								ps->flags |= PEER_F_HEARTBEAT;
 								appctx_wakeup(ps->appctx);
 							}
-							if (ps->appctx)
-								task->expire = tick_first(ps->reconnect, ps->heartbeat);
+							task->expire = tick_first(ps->reconnect, ps->heartbeat);
 						}
 					}
 					/* else do nothing */