msg/async: dec active connections when marked down

Otherwise, tests can't tell when a connection is stopped until it's eventually
"lazily" deleted. This should be safe since the perf counter is manipulating an
atomic value.

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit d2d38ac)

src/msg/async/AsyncMessenger.cc

@@ -860,7 +860,6 @@ int AsyncMessenger::accept_conn(AsyncConnectionRef conn)
     // If conn already in, we will return 0
     Mutex::Locker l(deleted_lock);
     if (deleted_conns.erase(existing)) {
-      existing->get_perf_counter()->dec(l_msgr_active_connections);
       conns.erase(it);
     } else if (conn != existing) {
       return -1;

src/msg/async/AsyncMessenger.h

@@ -315,7 +315,6 @@ class AsyncMessenger : public SimplePolicyMessenger {
     // lazy delete, see "deleted_conns"
     Mutex::Locker l(deleted_lock);
     if (deleted_conns.erase(p->second)) {
-      p->second->get_perf_counter()->dec(l_msgr_active_connections);
       conns.erase(p);
       return NULL;
     }
@@ -403,6 +402,7 @@ class AsyncMessenger : public SimplePolicyMessenger {
   void unregister_conn(AsyncConnectionRef conn) {
     Mutex::Locker l(deleted_lock);
     deleted_conns.insert(conn);
+    conn->get_perf_counter()->dec(l_msgr_active_connections);
 
     if (deleted_conns.size() >= ReapDeadConnectionThreshold) {
       local_worker->center.dispatch_event_external(reap_handler);