bad epg.el+GPG2 behavior: unavoidable passphrase pinentry prompt

[Ted Zlatanov]

It used to be possible to do

GPG_AGENT_INFO=none gpg --decrypt foo.gpg
GPG_AGENT_INFO=none gpg --batch --decrypt foo.gpg
etc.

but with GPG 2.x that seems to be disabled and the pinentry prompt pops
up no matter what.  Without waiting for changes on the GPG side, the
only option seems to be to downgrade to GPG 1.x, which is not a great
solution.  I haven't found a configuration option to disable the popup,
and even removing /usr/bin/pinentry and disabling the gpg-agent doesn't
work:

% unset GPG_AGENT_INFO
% gpg --batch --decrypt authinfo.gpg
gpg: CAST5 encrypted data
gpg-agent[28496]: can't connect to the PIN entry module: IPC connect call failed
gpg-agent[28496]: command get_passphrase failed: No pinentry
gpg: problem with the agent: No pinentry
gpg: encrypted with 1 passphrase
gpg: decryption failed: No secret key

The effect to Emacs users is that the pinentry passphrase dialog comes
up over and over, at least in X.  It makes working with .gpg files (in
VCS in particular) practically unusable and I haven't found a way to
disable the pinentry prompt.

I want to request either some workaroung or changes in epg.el or the
ability to use another encryption backend besides GPG,
e.g. http://ccrypt.sourceforge.net/

I am not opening a bug because it's not really a bug on our side IIUC.
Any advice is welcome... I hope I missed something in the GPG2 docs!

Thanks
Ted