Bug-1370: Support for four-octet AS number capability only.

-Both BGP speaker and peer, must advertise "support for four-octet AS number capability", to establish connection.

Change-Id: I2998e20439c12aca4e1a31660260d52f5d4963b5
Signed-off-by: Milos Fabian <milfabia@cisco.com>
Merge "Bug-1370: Support for four-octet AS number capability only."