force default to latin1 charset to allow upstream mysql cookbook merge

- we actually use utf8 but the fix for bug 993663 still seems to need
  latin1 initially.
- trying to merge upstream mysql cookbook fails, because commit
  38b3db4ce forces utf8 as a default
- this should allow upstream merge to pass
Merge pull request #15 from mancdaz/master

Merged automatically by jenkins after successful build test