coverity#1371219 Missing move assignment operator

Change-Id: I72ed6082b561079b45e82d8258fa1abbe23117e2
Reviewed-on: https://gerrit.libreoffice.org/29228
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

pyuno/inc/pyuno.hxx

@@ -102,6 +102,7 @@ public:
     }
 
     PyRef(const PyRef &r) : m(r.get()) { Py_XINCREF(m); }
+    PyRef(PyRef &&r) : m(r.get()) { r.scratch(); }
 
     ~PyRef() { Py_XDECREF( m ); }
 
@@ -121,6 +122,15 @@ public:
         return *this;
     }
 
+    PyRef& operator=(PyRef&& r)
+    {
+        PyObject *tmp = m;
+        m = r.get();
+        r.scratch();
+        Py_XDECREF(tmp);
+        return *this;
+    }
+
     bool operator == (  const PyRef & r ) const
     {
         return r.get() == m;