Allow LUs to declare lock levels required to be sequential
Allow LUs to declare lock levels required to be sequential

In many cases, an LU only needs a set of locks so that they
could as well be obtained all at once. In some cases, however,
the set of locks need at a particular lock level can only be
reliably determined if the locks at earlier levels are owned
already. The newly added instance variable dont_collate_locks
allows LUs to declare for which levels this is the case.

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

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