As per RFC 3246, the registry renames the name for DSCP 101110
(binary) from EF PHB to EF to clarify that a particular per-hop
behavior (PHB) is called expedited forwarding (EF).

Change-Id: I022c2fcd4bb42a210ae5c6ec62200b7c5a638250
Reviewed-on: https://go-review.googlesource.com/43695Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>