Remove `-protocol` command line argument.

[N. Taylor Mullen]

Today there's two commands that can be executed via the command line.

• resolve-protocol
• resolve-taghelpers

However, resolve-taghelpers can also take in a protocol argument to re-resolve the protocol. This isn't needed and should be removed. On removing it we should barf in the case that an invalid Protocol is provided.

[N. Taylor Mullen]

/cc @Eilon @danroth27 it'd be good to clean this up for rc2 (not a large change).

[N. Taylor Mullen]

Talked with @Eilon in person.

[N. Taylor Mullen]

b3874ce