mxqd: Reformulate server_is_qualified

Reformulate server_is_qualified to make it (IMO) easier to understand
and easier to expand.

mxqd.c

@@ -1405,29 +1405,23 @@ unsigned long start_job(struct mxq_group_list *glist)
 
 static int server_is_qualified(struct mxq_server *server, struct mxq_group *group) {
 
-    int is_qualified;
+    /* server in exclusive mode and no whitelist on group ? */
+    if ( server->daemon.daemon_flags && *group->group_whitelist == 0 )
+        return 0;
 
     if (*group->group_whitelist != 0) {
-        is_qualified = 0;
-        struct keywordset *kws = keywordset_new(group->group_whitelist);
-        if ( keywordset_ismember(kws, server->hostname_short)
-                || keywordset_ismember(kws, server->hostname) )
-            is_qualified = 1;
-        keywordset_free(kws);
-    } else {
-        if (server->daemon.daemon_flags)
-            return 0;  // exclusive
-        is_qualified = 1;
+        _mx_cleanup_(keywordset_free_byref) struct keywordset *kws = keywordset_new(group->group_whitelist);
+        if (! (keywordset_ismember(kws, server->hostname_short) || keywordset_ismember(kws, server->hostname)))
+            return 0;
     }
 
     if (*group->group_blacklist != 0) {
-        struct keywordset *kws = keywordset_new(group->group_blacklist);
-        if ( keywordset_ismember(kws, server->hostname_short)
-                || keywordset_ismember(kws, server->hostname) )
-            is_qualified = 0;
-        keywordset_free(kws);
+        _mx_cleanup_(keywordset_free_byref) struct keywordset *kws = keywordset_new(group->group_whitelist);
+        if (keywordset_ismember(kws, server->hostname_short) || keywordset_ismember(kws, server->hostname))
+            return 0;
     }
-    return (is_qualified);
+
+    return (1);
 }
 
 static int server_is_qualified_cached(struct mxq_server *server, struct mxq_group_list *glist) {