memory leak

[jsho000]

In the following code:

      int read_bytes = util::read_atmost_n(
                                  fdopen(err_rd_pipe, "r"),
                                  err_buf,
                                  SP_MAX_ERR_BUF_SIZ);
      close(err_rd_pipe);

The value returned by fdopen() is not closed. This causes memory leak.
If you call fclose(), it will close err_rd_pipe. So close(err_rd_pipe) is not necessary.

[arun11299]

@jsho000 Thank you for reporting. Can you provide a PR after testing the required changes ?

[arun11299]

Will be fixed with #104