Using gpg 1.4.18, doing "gpg --use-agent --gen-revoke $KEYID" with gpg-agent
2.1.1 causes the pinentry dialog box to appear, as it should.
if i enter the wrong password into three successive pinentry boxes, no
revocation certificate is emitted, but the return code is still 0.
The return code should be non-zero if the passphrase isn't provided directly.