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>