libxl: Resolve Coverity CHECKED_RETURN
libxl: Resolve Coverity CHECKED_RETURN

Add a check of the return for virDomainHostdevInsert() like every
other call.

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

elmarco/libvirt,rlaager/libvirt,jfehlig/libvirt,elmarco/libvirt,datto/libvirt,eskultety/libvirt,shugaoye/libvirt,agx/libvirt,libvirt/libvirt,shugaoye/libvirt,agx/libvirt,datto/libvirt,elmarco/libvirt,jfehlig/libvirt,zippy2/libvirt,VenkatDatta/libvirt,taget/libvirt,crobinso/libvirt,nertpinx/libvirt,crobinso/libvirt,shugaoye/libvirt,nertpinx/libvirt,zippy2/libvirt,eskultety/libvirt,jardasgit/libvirt,jfehlig/libvirt,andreabolognani/libvirt,datto/libvirt,rlaager/libvirt,taget/libvirt,eskultety/libvirt,rlaager/libvirt,fabianfreyer/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,olafhering/libvirt,nertpinx/libvirt,crobinso/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,olafhering/libvirt,taget/libvirt,elmarco/libvirt,nertpinx/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,zippy2/libvirt,jardasgit/libvirt,jardasgit/libvirt,andreabolognani/libvirt,elmarco/libvirt,libvirt/libvirt,agx/libvirt,olafhering/libvirt,shugaoye/libvirt,eskultety/libvirt,eskultety/libvirt,zippy2/libvirt,rlaager/libvirt,jardasgit/libvirt,jardasgit/libvirt,rlaager/libvirt,libvirt/libvirt,andreabolognani/libvirt,datto/libvirt,taget/libvirt,fabianfreyer/libvirt,agx/libvirt,VenkatDatta/libvirt,libvirt/libvirt,fabianfreyer/libvirt,taget/libvirt,agx/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,crobinso/libvirt,shugaoye/libvirt,olafhering/libvirt,datto/libvirt