improve check for createdb privileges during setup_db re: #4941

[mradamcox]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

This is a cherry-pick of data that has already been put in stable/4.4.x.

See #4947 for full description

Checklist

• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[coveralls]

Coverage remained the same at ?% when pulling bd12d9e on legiongis:cherry_pick_PR_4947_to_master into d0e0b71 on archesproject:master.