fix gpg support

[nodoubleg]

With gpg enabled, when trying to read a thread with a single gpg-signed message I get the following error:

Error detected while processing function <SNR>33_search_show_thread[1]..<SNR>33_show:
line    4:
ArgumentError: wrong number of arguments (given 1, expected 0)

and when trying to send a gpg-signed email, I get the following error:

Sending failed. Error message was: wrong number of arguments (given 1, expected 0)

I have the mail and mail-gpg gems installed, so it appears that a function is getting called incorrectly?