Fix incorrect format selection for renderbuffers (missing alpha channel)
Fix incorrect format selection for renderbuffers (missing alpha channel)

grimfang/panda3d,chandler14362/panda3d,chandler14362/panda3d,tobspr/panda3d,grimfang/panda3d,tobspr/panda3d,chandler14362/panda3d,grimfang/panda3d,tobspr/panda3d,tobspr/panda3d,grimfang/panda3d,tobspr/panda3d,tobspr/panda3d,chandler14362/panda3d,chandler14362/panda3d,chandler14362/panda3d,grimfang/panda3d,chandler14362/panda3d,tobspr/panda3d,chandler14362/panda3d,grimfang/panda3d,tobspr/panda3d,grimfang/panda3d,chandler14362/panda3d,grimfang/panda3d,grimfang/panda3d,tobspr/panda3d,grimfang/panda3d,chandler14362/panda3d,tobspr/panda3d