Fixed ammo status bar flickering

Fixed a bug where when picking up a load of ammo, the yellow ammo numbers would flicker until the MUG turned or if you fired your weapon.

source/st_stuff.c

@@ -388,9 +388,6 @@ static void ST_doRefresh(void)
 
 static boolean ST_NeedUpdate()
 {
-    if(_g->w_ready.oldnum != *_g->w_ready.num)
-        return true;
-
     if(_g->st_health.n.oldnum != *_g->st_health.n.num)
         return true;
 
@@ -399,6 +396,15 @@ static boolean ST_NeedUpdate()
 
     if(_g->w_faces.oldinum != *_g->w_faces.inum)
         return true;
+
+	// ammo
+    for(int i=0; i<4; i++)
+    {
+        if(_g->w_ammo[i].oldnum != *_g->w_ammo[i].num)
+            return true;
+		if(_g->w_maxammo[i].oldnum != *_g->w_maxammo[i].num)
+            return true;
+    }
 
     // weapons owned
     for(int i=0; i<6; i++)