remote-testgit: fix direction of marks

remote-testgit: fix direction of marks

Basically this is what we want:

  == pull ==

	testgit			transport-helper

	* export ->		import

	# testgit.marks		git.marks

  == push ==

	testgit			transport-helper

	* import		<- export

	# testgit.marks		git.marks

Each side should be agnostic of the other side. Because testgit.marks
(our helper marks) could be anything, not necessarily a format parsable
by fast-export or fast-import. In this test they happen to be compatible,
because we use those tools, but in the real world it would be something
completely different. For example, they might be mapping marks to
mercurial revisions (certainly not parsable by fast-import/export).

This is what we have:

  == pull ==

	testgit			transport-helper

	* export ->		import

	# testgit.marks		git.marks

  == push ==

	testgit			transport-helper

	* import		<- export

	# git.marks		testgit.marks

The only reason this is working is that git.marks and testgit.marks are
roughly the same.

This new behavior used to not be possible before due to a bug in
fast-export, but with the bug fixed, it works fine.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>