Add negative tests for endpoints

There were no negative tests that showed that the identity API
returns 400 Bad Request if an attempt is made to create or
update an endpoint with a non-Boolean value for the enabled
attribute.

Change-Id: I45db202c8231e02b5cf0514133976339e3a2f200
Related-Bug: #1282266
change teardown check to LOG.error

even with the warning message, this is completely confusing for
people when it shows up in the console logs. Instead lets just
log it at error level.

Change-Id: Iaa3a9d337adcfde9ddf702f8cfab1b9dc74c6559
Merge "change teardown check to LOG.error"
Merge "Add negative tests for endpoints"