By default, the output of floating point numbers by functions such as printf, wprintf...

So I change this behavior by using the function _set_output_format. Otherwise tesh detect an output difference in test file relative with send/receive and priority samples.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@5844 48e7efb5-ca39-0410-a469-dd3cf9ba447f