Add more error debug code to emfile test and refactor file reading
Add more error debug code to emfile test and refactor file reading

Change-Id: Icd47960d5dc459eff310ec46e5ecbd4767f8dd6d
Reviewed-on: http://review.couchbase.org/80989
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Jim Walker <1cd02e31b43620d7c664e038ca42a060d61727b9@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine