Make necessary change to make things work with photon 2.0 docker image.
Remove distro-sync to mitigate the build issue and add `--pull` to docker build
command to make sure the latest photon:2.0 will be pulled during build process.
Signed-off-by: Daniel Jiang <jiangd@vmware.com>
Previously the log file was set to a hard coded file, but given this
redis should run in container, the update is made to have the process
output log messages to standard output, and redirect it to syslog in
docker-compose template.
