virsh: plug memory leak on cmdDomIfGetLink() sucessful path
virsh: plug memory leak on cmdDomIfGetLink() sucessful path

Detected by valgrind. Leak introduced in commit dc675f3:

* tools/virsh.c: fix memory leak on cmdDomIfGetLink.

* how to reproduce?
  % valgrind -v --leak-check=full virsh domif-getlink <domain name> 0

* actual valgrind result:

==13102== 18 bytes in 1 blocks are definitely lost in loss record 9 of 47
==13102==    at 0x4A05FDE: malloc (vg_replace_malloc.c:236)
==13102==    by 0x322A6A67DD: xmlStrndup (in /usr/lib64/libxml2.so.2.7.6)
==13102==    by 0x414892: cmdDomIfGetLink (virsh.c:1538)
==13102==    by 0x4136A2: vshCommandRun (virsh.c:16363)
==13102==    by 0x4253FB: main (virsh.c:17865)
==13102==
==13102== LEAK SUMMARY:
==13102==    definitely lost: 18 bytes in 1 blocks
==13102==    indirectly lost: 0 bytes in 0 blocks
==13102==      possibly lost: 0 bytes in 0 blocks
==13102==    still reachable: 127,888 bytes in 1,361 blocks
==13102==         suppressed: 0 bytes in 0 blocks

Signed-off-by: Alex Jia <e236faec8cb8371bfb245ba3769a84afc9a11438@redhat.com>

jeckersb/libvirt,elmarco/libvirt,iam-TJ/libvirt,jeckersb/libvirt,jeckersb/libvirt,shugaoye/libvirt,agx/libvirt,taget/libvirt,datto/libvirt,emaste/libvirt,trainstack/libvirt,foomango/libvirt,rmarwaha/libvirt1,danwent/libvirt-ovs,wiedi/libvirt,shugaoye/libvirt,wiedi/libvirt,datto/libvirt,jeckersb/libvirt,rmarwaha/libvirt,jfehlig/libvirt,jardasgit/libvirt,agx/libvirt,rmarwaha/libvirt,iam-TJ/libvirt,VenkatDatta/libvirt,novel/fbsd-libvirt,libvirt/libvirt,shugaoye/libvirt,libvirt/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jeckersb/libvirt,warewolf/libvirt,emaste/libvirt,siboulet/libvirt-openvz,trainstack/libvirt,warewolf/libvirt,iam-TJ/libvirt,novel/fbsd-libvirt,novel/fbsd-libvirt,datto/libvirt,jardasgit/libvirt,cbosdo/libvirt,warewolf/libvirt,rlaager/libvirt,cbosdo/libvirt,rmarwaha/libvirt1,VenkatDatta/libvirt,warewolf/libvirt,eskultety/libvirt,cbosdo/libvirt,rlaager/libvirt,jeckersb/libvirt,bjzhang/libvirt,wiedi/libvirt,jfehlig/libvirt,olafhering/libvirt,danwent/libvirt-ovs,foomango/libvirt,siboulet/libvirt-openvz,jfehlig/libvirt,VenkatDatta/libvirt,dumbbell/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,danwent/libvirt-ovs,VenkatDatta/libvirt,datto/libvirt,novel/fbsd-libvirt,zippy2/libvirt,emaste/libvirt,novel/fbsd-libvirt,elmarco/libvirt,rmarwaha/libvirt,jardasgit/libvirt,zhlcindy/libvirt-1.1.4-maintain,jardasgit/libvirt,wiedi/libvirt,shugaoye/libvirt,olafhering/libvirt,agx/libvirt,crobinso/libvirt,iam-TJ/libvirt,novel/fbsd-libvirt,rmarwaha/libvirt1,nertpinx/libvirt,danwent/libvirt-ovs,bjzhang/libvirt,iam-TJ/libvirt,rmarwaha/libvirt,dumbbell/libvirt,bjzhang/libvirt,zippy2/libvirt,elmarco/libvirt,dumbbell/libvirt,wiedi/libvirt,iam-TJ/libvirt,taget/libvirt,datto/libvirt,wiedi/libvirt,zhlcindy/libvirt-1.1.4-maintain,rmarwaha/libvirt1,eskultety/libvirt,trainstack/libvirt,shugaoye/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,eskultety/libvirt,rmarwaha/libvirt,libvirt/libvirt,andreabolognani/libvirt,bjzhang/libvirt,agx/libvirt,iam-TJ/libvirt,rlaager/libvirt,danwent/libvirt-ovs,warewolf/libvirt,foomango/libvirt,rmarwaha/libvirt1,agx/libvirt,rlaager/libvirt,trainstack/libvirt,eskultety/libvirt,emaste/libvirt,dumbbell/libvirt,cbosdo/libvirt,jeckersb/libvirt,novel/fbsd-libvirt,emaste/libvirt,VenkatDatta/libvirt,olafhering/libvirt,zippy2/libvirt,nertpinx/libvirt,rmarwaha/libvirt,andreabolognani/libvirt,elmarco/libvirt,nertpinx/libvirt,crobinso/libvirt,dumbbell/libvirt,taget/libvirt,taget/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,trainstack/libvirt,warewolf/libvirt,olafhering/libvirt,zippy2/libvirt,jardasgit/libvirt,zhlcindy/libvirt-1.1.4-maintain,fabianfreyer/libvirt,emaste/libvirt,siboulet/libvirt-openvz,wiedi/libvirt,nertpinx/libvirt,elmarco/libvirt,eskultety/libvirt,warewolf/libvirt,zhlcindy/libvirt-1.1.4-maintain,foomango/libvirt,dumbbell/libvirt,andreabolognani/libvirt,trainstack/libvirt,taget/libvirt,rmarwaha/libvirt1,trainstack/libvirt,bjzhang/libvirt,rlaager/libvirt,emaste/libvirt,crobinso/libvirt,novel/fbsd-libvirt,novel/fbsd-libvirt,siboulet/libvirt-openvz,foomango/libvirt,siboulet/libvirt-openvz,libvirt/libvirt