Ecore animator: delete animater's internal timer in _end_tick() in all cases.

Ecore animator: delete animater's internal timer in _end_tick() in all cases.

When the ecore_animator_source_set() is called with different sources repeatedly, sometimes internal timer is not deleted and this leads animator misbehavior.
Especially when the source is changed from ECORE_ANIMATOR_SOURCE_TIMER to ECORE_ANIMATOR_SOURCE_CUSTOM before the SOURCE_TIMER's internal timer is deleted, this problem occurs.
In this case, even though _end_tick() is called in ecore_animator_source_set(), the SOURCE_TIMER's timer is not deleted because the source is already changed to CUSTOM.
So we should delete the internal timer in _end_tick() in all cases.