message: Add version number to redex-debug-line-map binary file
  Summary: As title.
diff: @@ -497,6 +497,7 @@ void write_debug_line_mapping(
  /*
  * Binary file format:
  * magic number 0xfaceb000 (4 byte)
  + * version number (4 byte)
  * number (m) of methods that has debug line info (4 byte)
  * a list (m elements) of:
  * [ encoded method-id (8 byte), method debug info byte offset (4 byte),
  @@ -514,11 +515,13 @@ void write_debug_line_mapping(
  // Start of debug line info information would be after all of
  // method-id => offset info, so set the start of offset to be after that.
  int binary_offset =
  - 2 * bit_32_size + (bit_64_size + 2 * bit_32_size) * num_method;
  + 3 * bit_32_size + (bit_64_size + 2 * bit_32_size) * num_method;
  std::ofstream ofs(debug_line_mapping_filename_v2.c_str(),
  std::ofstream::out | std::ofstream::trunc);
  uint32_t magic = 0xfaceb000; // serves as endianess check
  ofs.write((const char*)&magic, bit_32_size);
  + uint32_t version = 1;
  + ofs.write((const char*)&version, bit_32_size);
  ofs.write((const char*)&num_method, bit_32_size);
  FILE* fd = fopen(debug_line_mapping_filename.c_str(), "a");
  std::ostringstream line_out;
  