geoipupdate: update to 2.2.1

- `geoipupdate` now verifies the MD5 of the new database before deploying it.
  If the database MD5 does not match the expected MD5, `geoipupdate` will
  exit with an error.
- The copy of `base64.c` and `base64.h` was switched to a version under GPL 2+
  to prevent a license conflict.
- The `LICENSE` file was added to the distribution.
- Several issues in the documentation were fixed.

Signed-off-by: Lei Maohui <leimaohui@cn.fujitsu.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>