Why did Veeru not kill Gabbar Singh in Sholay?

The original ending that Ramesh Sippy wanted [and had actually shot] Sholay had Thakur jumping on Gabbar and strangling him to death. The ending was changed because of the Indian Censor Board’s stand on not allowing a former police officer taking the law into his own hands. Therefore many films during that period ended with cops coming out of nowhere and shouting hands up, just when the villain was about to be killed. 

[youtube:http://www.youtube.com/watch?feature=player_detailpage&v=z9ST8u-ZOiQ#t=0]