Don't decrypt twice

According to #13328, the minion was stacktracing on state but
operating normally after that.

I believe this problem may have originated in the channel-reuse
changes in #13155. It appears that the intention there may have
been to move the crypt functionality into the transport, which
would make it unecessary in the minion method itself. (Please
correct me if I'm wrong, of course. I'm making an assumption here.)

At any rate, this removes that duplicate functionality, thus
eliminating the stack trace.
Merge pull request #13334 from cachedout/13328

Don't decrypt twice