Description of problem:
cmd vcpupin output wrong info if vcpu bind to a not exist cpu in config

Version-Release number of selected component (if applicable):
libvirt-1.3.2-1.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.
# virsh dumpxml rhel7.0-rhel
...
  <cputune>
    <vcpupin vcpu='0' cpuset='30'/>
    <emulatorpin cpuset='30'/>
  </cputune>
...

2.
# lscpu 
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
...


3.
# virsh vcpupin rhel7.0-rhel --config
VCPU: CPU Affinity
----------------------------------
   0: 

# virsh emulatorpin rhel7.0-rhel --config
emulator: CPU Affinity
----------------------------------
       *: 



Actual results:
cmd vcpupin/emulatorpin output wrong info if vcpu bind to a not exist cpu in config 

Expected results:
show the correct result

# virsh vcpupin rhel7.0-rhel --config
VCPU: CPU Affinity
----------------------------------
   0: 30

# virsh emulatorpin rhel7.0-rhel --config
emulator: CPU Affinity
----------------------------------
       *: 30



Additional info: