cmd/swarm: fail on SWARM_ENV_MAX_STREAM_PEER_SERVERS parsing error

cmd/swarm/config.go

@@ -313,9 +313,11 @@ func envVarsOverride(currentConfig *bzzapi.Config) (config *bzzapi.Config) {
 	}
 
 	if max := os.Getenv(SWARM_ENV_MAX_STREAM_PEER_SERVERS); max != "" {
-		if m, err := strconv.Atoi(max); err == nil {
-			currentConfig.MaxStreamPeerServers = m
+		m, err := strconv.Atoi(max)
+		if err != nil {
+			utils.Fatalf("invalid environment variable %s: %v", SWARM_ENV_MAX_STREAM_PEER_SERVERS, err)
 		}
+		currentConfig.MaxStreamPeerServers = m
 	}
 
 	if lne := os.Getenv(SWARM_ENV_LIGHT_NODE_ENABLE); lne != "" {