Strip items when using kartgiveitem

Fixes some annoyances I have when using this command

src/d_netcmd.c

@@ -5359,6 +5359,9 @@ static void Got_GiveItemcmd(UINT8 **cp, INT32 playernum)
 		return;
 	}
 
+	K_StripItems(&players[playernum]);
+	players[playernum].itemroulette = 0;
+
 	players[playernum].itemtype   = item;
 	players[playernum].itemamount = amt;
 }