SFT: avoid testing aggregator features

SFT: avoid testing aggregator features

Feature repositories built by the Karaf Maven plugin contain an
aggregator feature which pulls in all the features in the relevant
POM. It's pointless to test this, and very expensive, so we now skip
them: the rule is that, in repositories with more than one feature,
any feature with the same name as the repository is skipped.
(Repositories containing a single feature are tested, so that single
features can be checked in -Psft mode.)

Change-Id: I8ca11e9ff18663e62cee94e3203b5a0e0db17742
Signed-off-by: Stephen Kitt <skitt@redhat.com>