Upgrade from Jetty 7.3.1 to Jetty 7.6.8

This fix is in relation to Trac ticket 1295.

http://osgeo-org.1560.x6.nabble.com/GeoNetwork-opensource-Developer-website-1295-JSP-and-UTF-8-td5055951.html

The original error seems related to UTF-8 but after applying some UTF-8 fixes the bug would still appear.

Simple step to reproduce the bug. 
- stop and start the jetty server
- go to the following url   http://localhost:8080/geonetwork/srv/eng/admin

This patch is for upgrading 7.3.1 to 7.6.8.  It seems to have fixes the issue with jsp pages not being compiled properly on initial load.  I'm no longer able to reproduce the bug.

Note: The change removed jetty 7.3.1 and 6.1.14(not sure why this existed)

As this is a fairly big change it may require more extensive testing before applying this change.