conf: Fix error path in virNodeDevPCICapabilityParseXML
conf: Fix error path in virNodeDevPCICapabilityParseXML

If the call to virXPathNodeSet to set naddresses fails, Coverity notes
that the subsequent VIR_ALLOC_N cannot have a negative value (well it
probably wouldn't be negative per se).

Signed-off-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>

jardasgit/libvirt,jfehlig/libvirt,andreabolognani/libvirt,libvirt/libvirt,andreabolognani/libvirt,eskultety/libvirt,olafhering/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,crobinso/libvirt,libvirt/libvirt,VenkatDatta/libvirt,libvirt/libvirt,datto/libvirt,VenkatDatta/libvirt,crobinso/libvirt,taget/libvirt,crobinso/libvirt,crobinso/libvirt,olafhering/libvirt,olafhering/libvirt,taget/libvirt,jardasgit/libvirt,nertpinx/libvirt,zippy2/libvirt,eskultety/libvirt,jardasgit/libvirt,zippy2/libvirt,nertpinx/libvirt,taget/libvirt,eskultety/libvirt,jardasgit/libvirt,eskultety/libvirt,andreabolognani/libvirt,nertpinx/libvirt,zippy2/libvirt,datto/libvirt,nertpinx/libvirt,olafhering/libvirt,jfehlig/libvirt,datto/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,taget/libvirt,eskultety/libvirt,zippy2/libvirt,datto/libvirt,VenkatDatta/libvirt,libvirt/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,datto/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,taget/libvirt,jardasgit/libvirt