Bug#926547: insserv: tests/run-tests are not used

[Jesse Smith]

Thanks for the ping, I did not see this one come in for some reason.

I have added the testsuite to the Makefile's "check" target and
addressed the unset variable issue.

Going through the tests, figuring out which ones are failing and why
will take a little longer. Or, for that matter, there may be cases where
failing is a good thing as some of the tests seem to be dealing with
situations where the data is problematic and we need to bomb out. I'll
check.

- Jesse