Add Router Association testcase

Add Router Association testcase

JIRA: SDNVPN-49

This functional test is a variant of testcase 1. Instead of associating
Network 1 and Network 2 to the BGP VPN, we connect Network 1 to a
router and associate that router and Network 2 to the VPN.

The testcase is disabled for now.

Test setup procedure:
- Set up VM1 and VM2 on Node1 and VM3 on Node2, all having ports in the
  same Neutron Network N1 and having 10.10.10/24 addresses in subnet
  SN1. N1/SN1 are connected to router R1.
- Set up VM4 on Node1 and VM5 on Node2, both having ports in Neutron
  Network N2 and having 10.10.11/24 addresses in subnet SN2.

Test execution:
1. Create VPN1 with eRT<>iRT and associate R1 to it
 - Ping from VM1 to VM2 should work
 - Ping from VM1 to VM3 should work
- Ping from VM1 to VM4 should not work
2. Associate SN2 to VPN1
 - Ping from VM4 to VM5 should work
 - Ping from VM1 to VM4 should not work
 - Ping from VM1 to VM5 should not work
3. Change VPN1 so that iRT=eRT
 - Ping from VM1 to VM4 should work
 - Ping from VM1 to VM5 should work

Jira task in SDNVPN: https://jira.opnfv.org/browse/SDNVPN-49

Change-Id: I0e805b042eb645e923f1639179c4c2c37be17835
Signed-off-by: George Paraskevopoulos <geopar@intracom-telecom.com>