Check user restriction DISALLOW_REMOVE_USER in isProvisioningAllowed.

If DISALLOW_REMOVE_USER is set and there is already a managed profile:
isProvisioningAllowed() should return false

BUG:32629873
Test: adb shell am instrument -e class com.android.server.devicepolicy.DevicePolicyManagerTest -w
com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner
Change-Id: I093bed0a4a54f83decf11716ebfd50dd4f17c089
2 files changed