Only output initialized capabilities with VIR_TEST_DEBUG > 1

Only output initialized capabilities with VIR_TEST_DEBUG > 1

Currenty virTestInit() outputs all capabilities that it created when running
with VIR_TEST_DEBUG=1.  Since this is quite a lot of output for every call of
this function (and it is not needed until debugging a really deep-down issue)
let's just output the info when VIR_TEST_DEBUG is strictly greater than 1.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>