spec: struct tags must be identical for types to be identical
spec: struct tags must be identical for types to be identical

We didn't mention this explicitly during our discussions,
but I think it fits the "identical types are spelled identically"
rule that we used.

R=gri, iant, ken2, r, rsc1
CC=golang-dev
http://codereview.appspot.com/1698043

nightlyone/golang,pombredanne/go-deleteme,nightlyone/golang,ssrl/go,dsriram/golang,dsriram/golang,gnanderson/go,ssrl/go,h8liu/golang,nightlyone/golang,h8liu/golang,tv42/old-go,ssrl/go,tianon/debian-golang,dsriram/golang,apparentlymart/golang,h8liu/golang,pombredanne/go-deleteme,apparentlymart/golang,gnanderson/go,dsriram/golang,tv42/old-go,dsriram/golang,apparentlymart/golang,tv42/old-go,pombredanne/go-deleteme,ssrl/go,ssrl/go,bdwalton/debian-golang,tv42/old-go,apparentlymart/golang,bdwalton/debian-golang,dsriram/golang,bdwalton/debian-golang,pombredanne/go-deleteme,tianon/debian-golang,tianon/debian-golang,pombredanne/go-deleteme,apparentlymart/golang,h8liu/golang,tv42/old-go,tianon/debian-golang,bdwalton/debian-golang,bdwalton/debian-golang,nightlyone/golang,gnanderson/go,nightlyone/golang,gnanderson/go,apparentlymart/golang,tianon/debian-golang,tv42/old-go,gnanderson/go,dsriram/golang,apparentlymart/golang,tv42/old-go,ssrl/go,tianon/debian-golang,pombredanne/go-deleteme,bdwalton/debian-golang,ssrl/go,tianon/debian-golang,h8liu/golang,nightlyone/golang,pombredanne/go-deleteme,nightlyone/golang,gnanderson/go,bdwalton/debian-golang,bdwalton/debian-golang,h8liu/golang,h8liu/golang,tianon/debian-golang,gnanderson/go