minor fixes for x2 + modify conf files

The configuration file has now to contain ENB_IPV4_ADDRESS_FOR_X2C and
ENB_PORT_FOR_X2C in the NETWORK_INTERFACES section.

For example:

    NETWORK_INTERFACES :
    {
        ENB_INTERFACE_NAME_FOR_S1_MME            = "eth0";
        ENB_IPV4_ADDRESS_FOR_S1_MME              = "192.168.12.111/24";
        ENB_INTERFACE_NAME_FOR_S1U               = "eth0";
        ENB_IPV4_ADDRESS_FOR_S1U                 = "192.168.12.111/24";
        ENB_PORT_FOR_S1U                         = 2152; # Spec 2152

        ENB_IPV4_ADDRESS_FOR_X2C                 = "192.168.12.111/24";
        ENB_PORT_FOR_X2C                         = 36422; # Spec 36422
    };
18 jobs for <span class="ref-name">x2</span> in 0 seconds (queued for 11 minutes and 29 seconds)
Status Job ID Name Coverage
  External
passed Analysis with cppcheck

00:06:43

passed Build UE-ethernet

00:08:28

passed Build basic-sim

00:12:00

passed Build eNb-USRP

00:10:30

passed Build eNb-USRP-CentOS

00:06:11

passed Build eNb-ethernet

00:08:59

passed Build phy-sim

00:08:59

passed Test phy-sim

00:09:57

failed Test-FDD-Band7

00:34:37

passed Analysis with cppcheck

00:06:41

passed Build UE-ethernet

00:08:29

passed Build basic-sim

00:12:14

passed Build eNb-USRP

00:10:29

passed Build eNb-USRP-CentOS

00:05:57

passed Build eNb-ethernet

00:08:44

passed Build phy-sim

00:07:44

passed Test phy-sim

00:10:17

failed Test-FDD-Band7

00:03:36