Implement more thorough error checks:

Implement more thorough error checks:

- Check the return value of every relevant function call.

- If BIO_new() returns NULL instead of a valid BIO, do not attempt to
  blindly use the NULL value as a BIO throughout the rest of the code.

- Ensure that bio_out is freed by BIO_free_all() at the end of all
  error paths.

ok doug@