Fix the remaining LUMINANCE* cases in rgba8_image_to_tex_image_data
Fix the remaining LUMINANCE* cases in rgba8_image_to_tex_image_data

nnethercote/servo,DominoTree/servo,nnethercote/servo,peterjoel/servo,KiChjang/servo,larsbergstrom/servo,nnethercote/servo,splav/servo,notriddle/servo,larsbergstrom/servo,KiChjang/servo,paulrouget/servo,larsbergstrom/servo,sadmansk/servo,nnethercote/servo,paulrouget/servo,DominoTree/servo,jimberlage/servo,pyfisch/servo,paulrouget/servo,peterjoel/servo,pyfisch/servo,paulrouget/servo,saneyuki/servo,larsbergstrom/servo,jimberlage/servo,emilio/servo,sadmansk/servo,DominoTree/servo,larsbergstrom/servo,szeged/servo,pyfisch/servo,SimonSapin/servo,KiChjang/servo,emilio/servo,paulrouget/servo,pyfisch/servo,notriddle/servo,szeged/servo,KiChjang/servo,pyfisch/servo,peterjoel/servo,DominoTree/servo,splav/servo,peterjoel/servo,peterjoel/servo,pyfisch/servo,larsbergstrom/servo,larsbergstrom/servo,emilio/servo,peterjoel/servo,KiChjang/servo,sadmansk/servo,KiChjang/servo,SimonSapin/servo,paulrouget/servo,notriddle/servo,sadmansk/servo,DominoTree/servo,saneyuki/servo,KiChjang/servo,DominoTree/servo,saneyuki/servo,nnethercote/servo,pyfisch/servo,nnethercote/servo,larsbergstrom/servo,SimonSapin/servo,jimberlage/servo,DominoTree/servo,splav/servo,nnethercote/servo,peterjoel/servo,DominoTree/servo,szeged/servo,larsbergstrom/servo,sadmansk/servo,szeged/servo,saneyuki/servo,jimberlage/servo,emilio/servo,larsbergstrom/servo,emilio/servo,sadmansk/servo,szeged/servo,splav/servo,emilio/servo,notriddle/servo,DominoTree/servo,pyfisch/servo,SimonSapin/servo,splav/servo,saneyuki/servo,peterjoel/servo,splav/servo,splav/servo,pyfisch/servo,saneyuki/servo,notriddle/servo,KiChjang/servo,SimonSapin/servo,nnethercote/servo,sadmansk/servo,szeged/servo,szeged/servo,emilio/servo,szeged/servo,DominoTree/servo,emilio/servo,jimberlage/servo,paulrouget/servo,saneyuki/servo,saneyuki/servo,notriddle/servo,jimberlage/servo,saneyuki/servo,jimberlage/servo,SimonSapin/servo,emilio/servo,jimberlage/servo,splav/servo,pyfisch/servo,KiChjang/servo,szeged/servo,notriddle/servo,peterjoel/servo,nnethercote/servo,paulrouget/servo,saneyuki/servo,sadmansk/servo,SimonSapin/servo,splav/servo,notriddle/servo,SimonSapin/servo,peterjoel/servo,notriddle/servo,paulrouget/servo,emilio/servo,splav/servo,nnethercote/servo,szeged/servo,KiChjang/servo,notriddle/servo,jimberlage/servo,paulrouget/servo