Make TestLock an instance of Lock
Make TestLock an instance of Lock

Equip the type of test locks with a simple group structure
consisting of two lock groups and a big lock.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Petr Pudlak <9d19625f8ee825a2c398462ed335cbcf98f79c32@google.com>

yiannist/ganeti,andir/ganeti,bitemyapp/ganeti,yiannist/ganeti,andir/ganeti,ganeti-github-testing/ganeti-test-1,onponomarev/ganeti,andir/ganeti,grnet/snf-ganeti,apyrgio/ganeti,ganeti/ganeti,dimara/ganeti,dimara/ganeti,apyrgio/ganeti,ganeti/ganeti,mbakke/ganeti,grnet/snf-ganeti,ganeti/ganeti,onponomarev/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,leshchevds/ganeti,bitemyapp/ganeti,leshchevds/ganeti,mbakke/ganeti,yiannist/ganeti,mbakke/ganeti