Veteran Democratic gay activist Allen Roskoff skewered some adversaries with the invite to his annual holiday party in Chelsea the other night. The Photoshopped version of “Gone With the Wind” showed East Side Assemblyman Micah Kellner as Clark Gable and losing Manhattan district attorney candidate Leslie Crocker Snyder, as Vivian Leigh, in his arms, and identified as “Leslie Cocker Spaniel.” Roskoff read bogus regrets from state Sen. Hiram Monserrate (who recently stood trial for slashing his girlfriend’s face). The Bronx pol supposedly was busy filming a sequel to “Texas Chainsaw Massacre.” Joining in the laughter were City Comptroller William Thompson, his successor, John Liu, State Sen. Eric Schneiderman, Assemblymen Dick Gottfried and Jonathan Bing, City Councilwoman Rosie Mendez, former Public Advocate Mark Green and cable porn queen Robin Byrd.