Fix most end-to-end issues with testcase 3 and reenable it

Fix most end-to-end issues with testcase 3 and reenable it

- Make the test work end-to-end on Fuel
- Use the instance log to verify quagga started
- Don't attempt to check for peering, as that is for
a future release
- Use the external IP of the controller for peering
- Fix not getting the output of OpenDaylight commands

Change-Id: Ia7bb533ab65e0fca6b7f48bb64133f6d8f3ff8ae
JIRA: SDNVPN-114
Signed-off-by: Romanos Skiadas <rski@intracom-telecom.com>
(cherry picked from commit 6674049b09d02fe0dc7e11e007e710643cdd49ca)