mlv_rec: eliminate PROPAD_GetPropertyData, get camera model and serial info from core (should fix #2460)
Created originally on Bitbucket by dmilligan (David Milligan)
See: https://bitbucket.org/hudson/magic-lantern/pull-requests/619/1100d-propad_getpropertydata-stub/diff
@a1ex: "I'd rather refactor the code to use a plain prop handler, or get the values from the core, then remove this stub."
Tested on 60D