Fix leak in virDomainVcpuPinDefArrayFree

If virDomainVcpuPinDefArrayFree is called with def != NULL,
but nvcpupin == 0, then it leaks memory for 'def'. This is
an unusual scenario, but it hits when cleaning up after an
OOM during parsing of XML.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/conf/domain_conf.c

@@ -1854,7 +1854,7 @@ virDomainVcpuPinDefArrayFree(virDomainVcpuPinDefPtr *def,
 {
     size_t i;
 
-    if (!def || !nvcpupin)
+    if (!def)
         return;
 
     for (i = 0; i < nvcpupin; i++) {