This option is unneeded because `bitcoin-cli` auth and connection
settings are already provided by other options like `bitcoin-rpcpassword`.
In bitcoind versions prior to 29.0, option `datadir` (passed by clightning to `bitcoin-cli`)
was therefore ignored.
Since 29.0, option `datadir` is always checked for validity. This causes a
file permission error because service clighting has no access to the
bitcoin datadir. This is now fixed.
Erik Arvstedt
815f2cd325