blame: correctly handle files regardless of autocrlf

If a file contained CRLF line endings in a repository with
core.autocrlf=input, then blame always marked lines as "Not
Committed Yet", even if they were unmodified.  Don't attempt to
convert the line endings when creating the fake commit so that blame
works correctly regardless of the autocrlf setting.

Reported-by: Ephrim Khong <dr.khong@gmail.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>