As part of the "clear connection configuration for reused objects"
patch, a ::stop would reset the self-signed, trust anchors, etc.
WiFiClient, unfortunately, calls ::stop as part of the connection
process, so all of these settings were lost.
Now only clear the connection settings on ::stop if we've already
been connected.
Also update the github public key which changed yet again.
Fixes#5086
cd43337f4f