Don't try and use clover optimised test runs.

As the tests now take about 3 seconds there's no point using clover
to try and reduce how many we run. This simplifies the build file
and will hopefully fix the double-test issues.

Change-Id: I1f689e8c5a1620a79fa64574d91012be207b1468
Fixes-issue: INFRA-62
Reviewed-on: http://gerrit.dmdirc.com/2702
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager