mxqd: Go into WAITING less frequently

Only advertise WAITING state if there are jobs which could be started
on this server.

mxqd.c

@@ -1428,6 +1428,14 @@ static int can_start_job(struct mxq_group_list *group, unsigned long df_scratch,
     return 1;
 }
 
+static int can_start_job_for_user(struct mxq_user_list *user, unsigned long df_scratch, struct mxq_server *server, long slots_to_start) {
+    /* Can we start a(nother) job for this user? */
+    for (struct mxq_group_list *group = user->groups; group; group = group->next)
+        if (can_start_job(group, df_scratch, server, slots_to_start))
+            return 1;
+    return 0;
+}
+
 unsigned long start_user(struct mxq_user_list *ulist, long slots_to_start, unsigned long df_scratch)
 {
     struct mxq_server *server;
@@ -1510,7 +1518,7 @@ long start_user_with_least_running_global_slot_count(struct mxq_server *server)
     for (ulist = server->users; ulist; ulist = ulist->next) {
         /* if a previous users is waiting for free resources, don't start jobs
          * for later users. */
-        if (waiting)
+        if (waiting && can_start_job_for_user(ulist, df_scratch, server, slots_free))
             /* returning -1 here tells the daemon to set its status in the
              * database to WAITING, which is just informational.  */
             return -1;