Leslie Van Houten, a follower of Charles Manson who was convicted of murder for stabbing Los Angeles grocer Leno LaBianca and his wife, Rosemary, to death, has been denied parole. California Gov. Gavin Newsom blocked Van Houten’s parole for the fifth time Tuesday, saying she “currently poses an unreasonable danger to society if released from prison at this time.” Van Houten, 72, was 19 when she and a group of cult members broke into the LaBiancas’ home on Aug. 9, 1969, fatally stabbed them and then smeared their blood on the walls. A day earlier, Manson followers had murdered actress Sharon Ta…