Fix leak in virDomainDefParseXML parsing vcpupin

If virBitmapNew fails due to OOM, the 'vcpupin' variable
is leaked.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/conf/domain_conf.c

@@ -11194,8 +11194,10 @@ virDomainDefParseXML(xmlDocPtr xml,
             if (VIR_ALLOC(vcpupin) < 0)
                 goto error;
 
-            if (!(vcpupin->cpumask = virBitmapNew(VIR_DOMAIN_CPUMASK_LEN)))
+            if (!(vcpupin->cpumask = virBitmapNew(VIR_DOMAIN_CPUMASK_LEN))) {
+                VIR_FREE(vcpupin);
                 goto error;
+            }
             virBitmapCopy(vcpupin->cpumask, def->cpumask);
             vcpupin->vcpuid = i;
             def->cputune.vcpupin[def->cputune.nvcpupin++] = vcpupin;