Fix #5 in $scope.getAvailableRoles Only proceed with user roles
initialisation if USER elfin is available (Fix #5)
and in $rootScope.$on(HB_EVENTS.ELFIN_LOADED, function(event, elfin)
listener ony proceed with $scope.initWithUserRoles() if
$scope.availableRoles have been loaded.
changed getElfin signature adding hbEventType. This helps prevent double
event emission in putElfin where an HB_EVENTS.ELFIN_UPDATED need to be
emitted where previously, as a side effect of calling getElfin we have
an HB_EVENTS.ELFIN_LOADED as well.