• Fixing a potential, low memory null pointer dereference [thanks to @uhliarik].
• Fixing an incompatibility with a change in libcurl v7.66.0 that added unwanted
  "transfer-encoding" to POST requests. This failed in directy communication with
  Let's Encrypt boulder server (however it worked when accessed via the hosting CDN,
  as almost all live usages do). Thanks to @mkauf for finding and fixing.
• Fixes a compiler warning. False flag, but initialization to make it happy does not hurt.
  Thanks to @sundayoyeniyi for finding this. Refs #154.