Boston Police report arresting a third suspect yesterday for a March shooting on Quincy Street in Dorchester - after a foot chase that ended when the man tried but failed to hide in a closet in a home on Wakullah Street in Roxbury. Lashawn Scott, 19, was wanted for a shooting at 480 Quincy St. in Dorchester, around 2:50 p.m. on March 7 that sent the victim to the hospital with injuries not considered life threatening. Police say officers found "a Glock 45 with one round in the chamber and twelve rounds in a large capacity magazine" around the corner on Clarkson Street. Two other suspects had been arrested on April 1. Police say gang-unit officers spotted Scott around 12:30 p.m. yesterday in the area of Dudley Street and Mount Pleasant Avenue, briefly lost sight of him, then spotted him again running on Moreland Street.  A foot chase ensued, and the suspect ran into an open back door at 24 Wakullah Street.…