Make disallow add/remove managed profile restriction not global.

Otherwise: if the DO sets remove managed profile user restriction:
the profile owner of a managed profile cannot remove this managed
profile.

BUG:33854430
Test: adb shell am instrument -e class com.android.server.devicepolicy.DevicePolicyManagerTest -w
com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner
Change-Id: I90b2028ea627a2073298bf9ef3c07b4fdf8d13a1