It appears that this patch was applied (in commit
45616162db2d1e807dbe70e60c67cb701cbd06d8) with the virDomainIsActive(vm)
checks removed from qemudDomainCreate, such that we fail out with
"domain [...] is already defined and running" even if the domain is only
defined but not running.
The attached (completely trivial) patch (created against
301cbb70aa52db2d8c42bc9f9441366385f0a9c4) resolves this.