The Service class api changed a bit when defaults were added

Fix the api call to check for service attributes

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
Merge pull request #46 from battlemidget/patch-fix-service-call

The Service class api changed a bit when defaults were added
Merge service fix call

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>