Remove calls to non-existing com.nokia.devicelock D-Bus service

The nokia specific devicelock service is not available in Nemomobile
and thus the failing calls litter journal with error messages.

[mce] Remove calls to non-existing com.nokia.devicelock D-Bus service
Merge pull request #115 from spiiroin/no_nokia_devlock

Remove calls to non-existing com.nokia.devicelock D-Bus service