Handle syntax error offset being None
Handle syntax error offset being None

pyflakes/pyflakes,PyCQA/pyflakes,hugovk/frosted,timothycrosley/frosted,timothycrosley/frosted_original_fork,timothycrosley/frosted,epsy/pyflakes,mattcaldwell/frosted,jayvdb/pyflakes,nikolas/pyflakes,hugovk/frosted,asmeurer/pyflakes,bitglue/pyflakes