Don't double delete

src/core/surface/byte_buffer_queue.c

@@ -35,9 +35,9 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/useful.h>
 
-static void bba_destroy(grpc_bbq_array *array) {
+static void bba_destroy(grpc_bbq_array *array, size_t start_pos) {
   size_t i;
-  for (i = 0; i < array->count; i++) {
+  for (i = start_pos; i < array->count; i++) {
     grpc_byte_buffer_destroy(array->data[i]);
   }
   gpr_free(array->data);
@@ -53,8 +53,8 @@ static void bba_push(grpc_bbq_array *a, grpc_byte_buffer *buffer) {
 }
 
 void grpc_bbq_destroy(grpc_byte_buffer_queue *q) {
-  bba_destroy(&q->filling);
-  bba_destroy(&q->draining);
+  bba_destroy(&q->filling, 0);
+  bba_destroy(&q->draining, q->drain_pos);
 }
 
 int grpc_bbq_empty(grpc_byte_buffer_queue *q) {