[Remail] remail/gpg: Use the lists private key for signing

[Konstantin Ryabitsev]

On Tue, Feb 18, 2020 at 09:48:33PM +0100, Thomas Gleixner wrote:
> Konstantin reported that outgoing mail from a mailing list is signed with
> the default private key found in the private keyring.
> 
> That's caused by just handing boolen True into the sign argument of
> gpg_encrypt() while the documentation clearly says:
> 
>   sign (defaults to None)
>     Either the Boolean value True, or the fingerprint of a key which is
>     used to sign the encrypted data. If True is specified, the default key
>     is used for signing. When not specified, the data is not signed.
> 
> Hand the list account fingerprint in if signing is enabled in the
> configuration.
> 
> Reported-by: Konstantin Ryabitsev <konstantin at linuxfoundation.org>
> Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
> ---
> Note: Untested 

Tested and confirmed working.

Reviewed-by: Konstantin Ryabitsev <konstantin at linuxfoundation.org>


-K