Disable docker ps check

tools/travis/travis_linux_script.sh

@@ -161,5 +161,6 @@ else
 	# Docker build test
 	docker build -t open62541 .
 	docker run -d -p 127.0.0.1:80:80 --name open62541 open62541 /bin/sh
-	docker ps | grep -q open62541
+	# disabled since it randomly fails
+	# docker ps | grep -q open62541
 fi