olaclient can't create log as olad in Travis, running as root

[edlins]

From https://travis-ci.org/edlins/libPCA9685/builds/489310992 (build 268):

$ cat /var/log/olaclient.log
cat: /var/log/olaclient.log: No such file or directory
The command "cat /var/log/olaclient.log" exited with 1.

Current work-around is commenting out the cat command from .travis.yml.

[edlins]

Fixed olaclient unit file to run as root instead of olad. Need to confirm this actually works in dev env.