virsh: Don't print extra '-'s in error message for -k and -K options
virsh: Don't print extra '-'s in error message for -k and -K options

The error message contains one extra dash.

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