Avoid straying </cpuset>

by using the same condition as for the <cpuset>.

Fixes "make check" found by
    http://honk.sigxcpu.org:8001/job/libvirt-check/160/

src/conf/domain_conf.c

@@ -13687,8 +13687,8 @@ virDomainDefFormatInternal(virDomainDefPtr def,
         virBufferAsprintf(buf, "cpuset='%s'/>\n", cpumask);
         VIR_FREE(cpumask);
     }
-
-    if (def->cputune.shares || def->cputune.vcpupin ||
+    if (def->cputune.shares ||
+        (def->cputune.vcpupin && !virDomainIsAllVcpupinInherited(def)) ||
         def->cputune.period || def->cputune.quota ||
         def->cputune.emulatorpin ||
         def->cputune.emulator_period || def->cputune.emulator_quota)