fix crash in getAllDomainStats

Commits 1d39dba and 827ed9b broke the libvirt-python API by removing
virDomainRef() and virDomainFree().  virDomainStatsRecordListFree() will
free that domain pointer and later when virDomain (python object) call
its destructor and tries to free that same pointer again.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1326839

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>

libvirt-override.c

@@ -8381,6 +8381,7 @@ convertDomainStatsRecord(virDomainStatsRecordPtr *records,
     PyObject *py_retval;
     PyObject *py_record;
     PyObject *py_record_stats = NULL;
+    virDomainPtr dom = NULL;
     size_t i;
 
     if (!(py_retval = PyList_New(nrecords)))
@@ -8392,9 +8393,12 @@ convertDomainStatsRecord(virDomainStatsRecordPtr *records,
 
         VIR_PY_LIST_SET_GOTO(py_retval, i, py_record, error);
 
+        dom = records[i]->dom;
+        virDomainRef(dom);
         VIR_PY_TUPLE_SET_GOTO(py_record, 0,
-                              libvirt_virDomainPtrWrap(records[i]->dom),
+                              libvirt_virDomainPtrWrap(dom),
                               error);
+        dom = NULL;
 
         if (!(py_record_stats = getPyVirTypedParameter(records[i]->params,
                                                        records[i]->nparams)))
@@ -8406,6 +8410,8 @@ convertDomainStatsRecord(virDomainStatsRecordPtr *records,
     return py_retval;
 
  error:
+    if (dom)
+        virDomainFree(dom);
     Py_XDECREF(py_retval);
     return NULL;
 }