[0856] Added missing spawns of GO 175928

* Added missing spawns of gameobject 175928 (Incendia Agave)
* Uniformised respawn time for all GO (10 min)
* Put them all into a pool as the comments highly suggest they are (max
limit is guesswork based on comments)
Thanks TheTrueAnimal for pointing. This closes #646
Source: YTDB & UDB
http://www.wowhead.com/object=175928
http://www.wowhead.com/item=12732
[0857] Updated stats of creatures 7784, 7806 & 7807

* Updated armor and health of the three Homing Robots. They previously
had low life and 0 armor, making the quests more difficult to complete
Source: UDB
[0858] Applied SD2 update z2704

Removed quest 9180 - not available in classic

Signed-off-by: Cala <calaftp@free.fr>