libdm: no validate for pool without messages

Avoid validation of free space in pool, when no messages are passed.

Patch a3c7e326c3e9950fe74e433c406d6e1b5a53bf25 add new check for
pool overload - but this check should not be made if there are
no messages and transaction_id is still within 'bounds' (bigger by 1).
2 files changed