path_requests_run now generates a json file if -o is used
path_requests_run now generates a json file if -o is used

the format of path results follows the yang model of ietf

Signed-off-by: EstherLerouzic <9136e9bbec0a09a1685b8ebbe677b6c9b26e8f18@orange.com>

Telecominfraproject/gnpy