* rlp/rlpgen: remove build tag
This tag was supposed to prevent unstable output when types reference each other. Imagine
there are two struct types A and B, where a reference to type B is in A. If I run rlpgen
on type B first, and then on type A, the generator will see the B.EncodeRLP method and
call it. However, if I run rlpgen on type A first, it will inline the encoding of B.
The solution I chose for the initial release of rlpgen was to just ignore methods
generated by rlpgen using a build tag. But there is a problem with this: if any code in
the package calls EncodeRLP explicitly, the package can't be loaded without errors anymore
in rlpgen, because the loader ignores it. Would be nice if there was a way to just make it
ignore invalid functions during type checking (they're not necessary for rlpgen), but
golang.org/x/tools/go/packages does not provide a way of ignoring them.
Luckily, the types we use rlpgen with do not reference each other right now, so we can
just remove the build tags for now.
909dd4a109