CiviCRM Installer Errors - Can't change DB settings
There is an issue in the installer for 4.7.   I created https://issues.civicrm.org/jira/browse/CRM-19279  to track the issue.   With Christian's help I created a PR - https://github.com/civicrm/civicrm-core/pull/9029  I have tested this locally and on one of our test sites and it works.   

I'd appreciate any testing that can be done with this to make it a merge candidate.