Fix testcase3 (peering subcase) for Apex

Fix testcase3 (peering subcase) for Apex

 - Fix runnning bgp related commands on Karaf:
   update util.run_odl_cmd() in order to be able to
   run commands on karaf client. Otherwise karaf
   commands fail
 - Ensure zrpcd/bgpd to run on controller side properly:
   Add missing quagga run folder, change owner and
   add user quagga into quaggavt group, in case of apex
   installer
 - Update the way of handling br-ex information and
   parsing out the controller external ip and mask:
   In case we have multiple ip/netmask assigned on br-ex
   the separation was faulty and an extra line, containing
   the second ip address, was added into ext_net_mask variable

JIRA: SDNVPN-118

Change-Id: I62468c94fd945ba30e419bd30d9cd85502f28eeb
Signed-off-by: tomsou <soth@intracom-telecom.com>