domain_conf: Resolve Coverity COPY_PASTE_ERROR
domain_conf: Resolve Coverity COPY_PASTE_ERROR

Seems when commit id 'ea130e3b' added the checks to ensure each of
the hard_limit, soft_limit, and swap_hard_limit wasn't set at
VIR_DOMAIN_MEMORY_PARAM_UNLIMITED - a copy/paste error of using
the 'hard_limit' for each comparison was done. Adjust the code.

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