Fixup the bypassing example: pretend we've found v2 XML, and split the bypassing...

Fixup the bypassing example: pretend we've found v2 XML, and split the bypassing function in two (one for the platform and one for the application) to make sure that the platform isn't declared twice (once in MSG_create_environment and once in MSG_launch_application) since it fools things

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@4908 48e7efb5-ca39-0410-a469-dd3cf9ba447f