[lua_fix] focus_pos not reported correctly on 650d
Created originally on Bitbucket by AToe (AlexT)
focus_pos is not returned on 650d, tested with different lenses
#!lua printf("%d : %d\n", lens.focus_distance, lens.focus_pos)
is only returning " : focus_distance"
when running lens_focus() and lens.focus(), console shows Lens moving (0, 40000) or (0, 0) while focusing and 41000 or 1000 when focus soft limit is reached
tested same code with same lenses on 50d and got correct values printing focus_pos, but slightly different numbers from lens_focus() and lens.focus()