[Ansible-service-broker] Switched to logrus

[jesusr at redhat.com]

Go-logging required being initialized at app startup, which caused us
to do some interesting things to keep from having to pass the logger to
every method (we did this in the beginning). This and the fact that
bundle-lib and broker-client-go are already using logrus, prompted us
to change to logrus. It just works right out of the box, but still
allows for configuration to tweak it.

PR 961, merged this morning to switch from using go-logging to logrus
as the logging library. 
https://github.com/openshift/ansible-service-broker/pull/961

Some notes:

* broker logging configuration remains the same for now

* color option has been disabled because the default logrus color
output does not suit our needs. So changing the color setting in the
configuration will have no affect on the output right now.

* the broker logs will be consistent with the logs from bundle-lib and
broker-client-go again

* log.Notice(f) statements were replaced with log.Info(f) since logrus
does not have a Notice level.

>From a users point of view, you will notice different output in your
logs:
https://github.com/openshift/ansible-service-broker/pull/961#issuecomme
nt-390376937

If there are any questions or issues please reply to this thread or
ping us on freenode in #asbroker.

Sincerely,
jesus