Bug-1383: BGP listener should fail to configure if we do not have privileges

-verify if has root privileges, before BGP server is created.
-changed bgp's binding port initial configuration to 1790

Change-Id: Ic15c5c18ee773902b060fde733fe54f3a7a8526c
Signed-off-by: Milos Fabian <milfabia@cisco.com>