[travis] Fix a frequent test failure
caused by docker not being ready yet.
Travis builds often fail because the docker daemon
isn't running after we restart it. Sleep to give it some
time to restart.
@@ -43,6 +43,8 @@ case "$1" in
# restart the service for the /etc/default/docker change we made after
# installing the package
sudo restart docker
+ # Give it time to be ready
+ sleep 10
if [[ "$ENABLE_SWARM" = "1" ]]; then
# initialize docker swarm to be able to run docker tests
