Add button to change db ipaddress on readonly page

[Dave Morley]

Bug Description:
It would be great for testing purposes if on the readonly page there was a button that change the ip address of the master db. This would effectively create a failover test instance for us. Giving us the ability to test failover without interrupting anyone.

This requires readonly page being available in failover mode.

It would not effect the db's in any way and would mean that all data would be safe.

Allow it only to Admin/isd-hackers in debug mode only this should make the losas happy that it wouldn't be available in production also.

Version:
OS:
64bit Maverick

Browser:
FF 3.6.13

Problem URL:
<sso instance>/failover

Expected Result:
Access to readonly at all times, a button on readonly that changes the address for the master db and a second button that changes it back again. This enable us to test failover in a more rigorous manner, especially as staging now has the slave server in place it enables us to test readonly and failover correctly