qmp client: increase default fallback timeout to 5s

allowing slower or overloaded systems a higher chance to finish
commands while not being to long to be problematic for sync api calls
with their 30s total budget

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

PVE/QMPClient.pm

@@ -135,7 +135,9 @@ sub cmd {
 	 ) {
 	    $timeout = 10*60; # 10 mins ?
 	} else {
-	    $timeout = 3; # default
+	    #  NOTE: if you came here as user and want to change this, try using IO-Threads first
+	    # which move out quite some processing of the main thread, leaving more time for QMP
+	    $timeout = 5; # default
 	}
     }