ovs-l3ping: A new test utility that allows to detect L3 tunneling issues

ovs-l3ping: A new test utility that allows to detect L3 tunneling issues

ovs-l3ping is similar to ovs-test, but the main difference
is that it does not require administrator to open firewall
holes for the XML/RPC control connection. This is achieved
by encapsulating the Control Connection over the L3 tunnel
itself.

This tool is not intended as a replacement for ovs-test,
because ovs-test covers much broader set of test cases.

Sample usage:
Node1: ovs-l3ping -s 192.168.122.236,10.1.1.1 -t gre
Node2: ovs-l3ping -c 192.168.122.220,10.1.1.2,10.1.1.1 -t gre

Issue#11791
Signed-off-by: Ansis Atteka <aatteka@nicira.com>