domain_validate: Check for domain address conflicts fully

domain_validate: Check for domain address conflicts fully

Current implementation of virDomainMemoryDefCheckConflict() does
only a one way comparison, i.e. if there's a memory device within
def->mems[] which address falls in [mem->address, mem->address +
mem->size] range (mem is basically an iterator within
def->mems[]). And for static XML this works just fine. Problem is
with hot/cold plugging of a memory device. Then mem points to
freshly parsed memory device and these half checks are
insufficient. Not only we must check whether an existing memory
device doesn't clash with freshly parsed memory device, but also
whether freshly parsed memory device does not fall into range of
already existing memory device.

Resolves: https://issues.redhat.com/browse/RHEL-4452
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>