PR #421 still had open comments about leftover conditional statements

[Mischa Salle]

There were two open comments left in PR #421:
https://bitbucket.org/openid/connect/pull-requests/421#comment-363176223
https://bitbucket.org/openid/connect/pull-requests/421#comment-363176389

which are about the sentences

It MUST be present if the key doesn't have the revoked claim

and

It MUST be present if the key doesn't have the exp claim

but since exp is now still required, these two sentences no longer make sense.

[Giuseppe De Marco]

Resolved by https://bitbucket.org/openid/connect/pull-requests/428