Trunk 2873 : Improve wording for "Testing" option in installation wizard

This is my first intro ticket for OpenMRS.

I removed the lines that were described as unwanted. I deleted their corresponding English values in the messages.properties aswell.

The final undesired line didn't appear to be present.

I also changed the wording where it asks for your password as required. 

NOTE I handled the cases for English only.

Hopefully I've followed protocol correctly,