soup: avoid issues with mysql 5.7 and systemd

[dougburks]

There are 2 issues:

(1) soup tries to install mysql 5.5 but we're up to 5.7 now

(2) mysql_upgrade tries to connect to mysql and upgrade tables. This is problematic if we've disabled mysql via systemd. Looks like we'll have to enable mysql, do the upgrade, and then disable mysql (only if it was previously disabled).

documented:
https://github.com/Security-Onion-Solutions/security-onion/wiki/MySQL-Upgrade-Errors

[dougburks]

commit:
Security-Onion-Solutions/securityonion-sostat@6ac6926

[dougburks]

submitted for testing:
https://groups.google.com/d/topic/security-onion-testing/riC8fx0ufKc/discussion

[dougburks]

Published:
https://blog.securityonion.net/2018/08/securityonion-sostat-20120722.html