generic: Add a test for basic F_SETLEASE functionality

Add a new test that verifies that F_SETLEASE works as expected. The
parent opens a file and sets a lease on it and then forks. The child
then does a (possibly) conflicting open. We then verify that we get
signals as expected.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
5 files changed