Revised error handling for BGP update messages

A BGP message is considered to be malformed when any one of the message attributes is malformed. When a router participating in a BGP session receives a malformed update message, the entire session is reset by default. This is undesirable because update messages with valid routes are also affected. To avoid this undesirable behavior, the error handling for BGP update messages has been modified. To configure error handling for BGP update messages, configure the bgp-error-tolerance statement at the [edit protocols bgp], [edit protocols bgp group group-name], or [edit protocols bgp group group-name neighbor address] hierarchy level.