virt-aa-helper: test: check for expected profile content

virt-aa-helper: test: check for expected profile content

So far the virt-aa-helper tests only checked the return code and thereby
catched aborts like issues failing to parse the XML. But there is one
category of virt-aa-helper issues so far untested - not generating the
expected rule.

This adds a basic grep based checks after each test to match against the
rule that is expected to be added by the test.

Acked-by: Jamie Strandboge <jamie@canonical.com>
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>