Rename rwMutex to updateMutex

ipblocklist/firehol.go

 	ctxCancel context.CancelFunc
 	logger    mtglib.Logger
 
-	rwMutex sync.RWMutex
+	updateMutex sync.RWMutex
 
 	remoteURLs []string
 	localFiles []string
 		return true
 	}
 
-	f.rwMutex.RLock()
-	defer f.rwMutex.RUnlock()
+	f.updateMutex.RLock()
+	defer f.updateMutex.RUnlock()
 
 	if ip4 := ip.To4(); ip4 != nil {
 		return f.containsIPv4(ip4)
 	default:
 	}
 
-	f.rwMutex.Lock()
-	defer f.rwMutex.Unlock()
+	f.updateMutex.Lock()
+	defer f.updateMutex.Unlock()
 
 	f.treeV4 = v4tree
 	f.treeV6 = v6tree