BLTI-273

Bypass ServerConfigurationService.getServerUrl() when determining the incoming URL of a Request

The steps that LTI code will use to determine the current server URL are: 

- Consult the sakai.lti.serverUrl= property - default is nothing - allows override when all else fails - probably not needed 
- Consult the serverUrl= property - this will be the most typical path in production environments 
- Call ServerConfigurationServce.getServerUrl() - this will likely be the case in development environment 
- Use http://127.0.0.1:8080 if nothing else works - likely not to ever happen because ServerConfigurationServce.getServerUrl() has similar fall-through logic 




git-svn-id: https://source.sakaiproject.org/svn/basiclti/trunk@129200 66ffb92e-73f9-0310-93c1-f5514f145a0a