Use new get_mysql_endpoint method in osops-utils

Start converting various cookbooks to use the new #get_mysql_endpoint method
which now allows people to point to a non-chef managed mysql server for all
things.

See rcbops/chef-cookbooks#597
Merge pull request #3 from claco/issue-597

Use new get_mysql_endpoint method in osops-utils
use global 'region' attr
Merge pull request #4 from invsblduck/issue593_region

use global 'region' attr