Merge pull request #1506 from meshtastic/1504-proposal-default-short-name-to-mac-last-4

implement #1504

src/mesh/NodeDB.cpp

@@ -215,7 +215,7 @@ void NodeDB::installDefaultDeviceState()
     // Set default owner name
     pickNewNodeNum(); // based on macaddr now
     sprintf(owner.long_name, "Unknown %02x%02x", ourMacAddr[4], ourMacAddr[5]);
-    sprintf(owner.short_name, "?%02X", (unsigned)(myNodeInfo.my_node_num & 0xff));
+    sprintf(owner.short_name, "%02x%02x", ourMacAddr[4], ourMacAddr[5]);
 
     sprintf(owner.id, "!%08x", getNodeNum()); // Default node ID now based on nodenum
     memcpy(owner.macaddr, ourMacAddr, sizeof(owner.macaddr));