fix deprecated SAMFileReader reference

this needs ADAM 0.14.1, so maybe don't merge it in yet.
yea sorry, I just pulled this off of a branch that had all my latest versions of things.

I can revert it here but this PR is not ready for merging as-is anyway due to relying on an ADAM snapshot, so I was thinking of just leaving it until ADAM 0.14.1 is out.