util: Fix memory leak in virNetDevOpenvswitchInterfaceGetMaster
util: Fix memory leak in virNetDevOpenvswitchInterfaceGetMaster

Since 032548c4 @cmd was never autofree'd. Perhaps as a result of
VIR_AUTOPTR type changes occurring at roughly the same time so the
copy pasta missed this.

Found by Coverity.

Signed-off-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

olafhering/libvirt,libvirt/libvirt,crobinso/libvirt,zippy2/libvirt,nertpinx/libvirt,zippy2/libvirt,nertpinx/libvirt,nertpinx/libvirt,jfehlig/libvirt,jfehlig/libvirt,crobinso/libvirt,zippy2/libvirt,nertpinx/libvirt,zippy2/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,libvirt/libvirt,jfehlig/libvirt,olafhering/libvirt,nertpinx/libvirt,crobinso/libvirt,libvirt/libvirt,olafhering/libvirt,olafhering/libvirt