Reset the device policy machinery upon retrying enrollment.

BUG=chromium-os:18208
TEST=See bug description


Review URL: http://codereview.chromium.org/7676005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@97615 0039d316-1c4b-4281-b951-d872f2087c98
CloudPolicyCacheBase::~CloudPolicyCacheBase() {
  FOR_EACH_OBSERVER(Observer, observer_list_, OnCacheGoingAway(this));
}

CloudPolicyCacheBase::~CloudPolicyCacheBase() {
  FOR_EACH_OBSERVER(Observer, observer_list_, OnCacheGoingAway(this));
}
