This is mainly an internal-only change, especially since we don't
offer any globalfeatures.
However, LND (as of next release) will offer global features, and also
expect option_static_remotekey to be a *global* feature. So we send
our (merged) feature bitset as both global and local in init, and fold
those bitsets together when we get an init msg.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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