Add integration tests to check that only the given path is transferred

Add integration tests to check that only the given path is transferred

Until recently (it was fixed in ac2999a26a) when a path was transferred
other shares with the target user were removed, so a test was added to
ensure that it does not happen again.

Besides that a test to ensure that other files with the target user are
not transferred was added too (it did not fail before, but seemed
convenient to have that covered too :-) ).

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>