[PATCH] Preserve MED from eBGP peers

Hi all, The attached patch helps preserve MED values to/from eBGP peers. When propagating a route from a true eBGP peer to an internal peer, this avoids resetting the MED attribute to allow propagation of MED to/from external peers. This is enabled via a configuration line: "preserve med", which goes under BGP configs. Without the configuration line this would be a no-op. Thanks, Trisha -- *Trisha Biswas* | Sr. Software Engineer, Network Systems fastly.com | @fastly <https://twitter.com/fastly> | LinkedIn <http://www.linkedin.com/company/fastly>