Test_notifier contains a test case that verifies default notifier value
(test_get_default_notifier) and there are 2 test cases that update
default notifier value. It's supposed that test_get_default_notifier
is executed first, otherwise it gets wrong value. Test's tearDown()
method was designed to restore default notifier, but failed to do so
due to wrong reference to global variable.
Change-Id: Id083f1e8ba4bf2a0341eb1a7ee8891b53c1f3a65