nwfilter: Fix return value comparison for virNWFilterTriggerVMFilterRebuild
nwfilter: Fix return value comparison for virNWFilterTriggerVMFilterRebuild

Should compare < 0 to be correct.

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

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