Update functional tests for gnpy

Update functional tests for gnpy

- Mount the clliNetwork, openroadmNetwork and
openroadmTopology
- Test the case where path computed by PCE is not feasible and
 Gnpy computes a new one feasible
- Test the case where path computed by PCE is not feasible and
Gnpy cannot find a new one
- Test the case where path computed by PCE is feasible and
Gnpy confirms the feasibility
- Unmount the clliNetwork, openroadmNetwork and
openroadmTopology

JIRA: TRNSPRTPCE-132
Change-Id: If07482af397b419e42f810053e36c894f1668922
Signed-off-by: atriki <ahmed.triki.tn@gmail.com>