CI for ESP32 working again

Recently, LMIC continuous-integration builds for ESP32 have been broken (issue #691).

I found that options were rearranged sometime between 1.0.3 and 1.0.6 of the ESP board support package. Removing the offending option was sufficient to pass the compile tests, so that’s what I did.

You won’t see a change in the LMIC repo, because the problem was fixed in a helper repo, mcci-catena-ci, pull request #2.