correct blame for files commited with CRLF

correct blame for files commited with CRLF

git blame reports lines as not "Not Committed Yet" when they have
CRLF in the index, CRLF in the worktree and core.autocrlf is true.

Since commit c4805393 (autocrlf: Make it work also for un-normalized
repositories, 2010-05-12), files that have CRLF in the index are not
normalized at commit when core.autocrl is set.

Add a call to read_cache() early in fake_working_tree_commit(),
before calling convert_to_git().

Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>