Check return value of flush_character_buffer()

CID 486663

diff --cc Modules/pyexpat.c
index 82d9d6a9160d17a1833bdeb9c12d4245432a6457,07b1348d37803544768289b0be4ca895fc0676c5..87cec920418f0ead9637407c4062d0357eb7d207
--- 1/Modules/pyexpat.c
--- 2/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@@ -1521,12 -1503,14 +1521,14 @@@ xmlparse_setattro(xmlparseobject *self
        if (self->buffer != NULL) {
          /* there is already a buffer */
          if (self->buffer_used != 0) {
-           flush_character_buffer(self);
+             if (flush_character_buffer(self) < 0) {
+                 return -1;
+             }
          }
          /* free existing buffer */
 -        free(self->buffer);
 +        PyMem_Free(self->buffer);
        }
 -      self->buffer = malloc(new_buffer_size);
 +      self->buffer = PyMem_Malloc(new_buffer_size);
        if (self->buffer == NULL) {
          PyErr_NoMemory();
          return -1;