fsck: add a few committer name tests

fsck: add a few committer name tests

fsck reports "missing space before <email>" for committer string equal
to "name email>" or to "". It'd be nicer to say "missing email" for
the second string and "name is bad" (has > in it) for the first one.
Add a failing test for these messages.

For "name> <email>" no error is reported. Looks like a bug, so add
such a failing test."

Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>