Instance API #show should check provider account is not null

Instances created in non-test environment may have null as its
provider_account_id.
Merge pull request #317 from rwsu/instances-show-bug-fix

Instance API #show should check provider account is not null
Edit src/config/compass.rb to match newest compass reqs

This removes three lines from src/config/compass.rb because they
are incompatible with the newest upstream version of rubygem-compass.
Merge pull request #316 from eggmaster/compass-fix

Edit src/config/compass.rb to match newest compass reqs