message: fix a bug in OpenGL
diff: @@ -1824,7 +1824,7 @@ UMat mapGLBuffer(const Buffer& buffer, AccessFlag accessFlags)
  switch (accessFlags & (ACCESS_READ|ACCESS_WRITE))
  {
  default:
  - case ACCESS_READ|ACCESS_WRITE:
  + case ACCESS_READ+ACCESS_WRITE:
  clAccessFlags = CL_MEM_READ_WRITE;
  break;
  case ACCESS_READ:
  