virsh: report error if vcpu number exceed the guest maxvcpu number

virsh: report error if vcpu number exceed the guest maxvcpu number

Commit id '81dd81e' caused a regression when attempting to print a
specific vcpuid that is out of the range of the maximum vcpus for
the guest, such as:

 $ virsh vcpupin $dom 1000
 VCPU: CPU Affinity
 ----------------------------------

 $

Rather than just recover the old message, let's adjust the message based
on what would be displayed for a similar failure in the set path, such as:

 $ virsh vcpupin $dom 1000
 error: vcpu 1000 is out of range of persistent cpu count 2

 $ virsh vcpupin $dom 1000 --live
 error: vcpu 1000 is out of range of live cpu count 2

 $

Signed-off-by: Luyao Huang <lhuang@redhat.com>