We should write a test to validate the behaviour of the global critical section.

Roughly, we should evaluate the following sequence of events:
ASSERT: User X with readWrite@foo can insert into foo.
ASSERT: Administrative user A may enable write blocking mode.
ASSERT: X receives a semantically meaningful error message if it attempts to insert into foo.
ASSERT: User R authorized with the restore role may insert into foo
ASSERT: A may disable write blocking mode
ASSERT X may insert into foo

We should run this test on a standalone and a 3 node replicaset. Until SERVER-63459 we should only validate replicaset behaviour on the primary.