(Re)Signing does not work

[spinscale]

I am running rpm-s3 with the --sign option, however I am not queried for my passphrase. This is what is logged, looks as if pexpect does not kick in

rpm-s3/bin/rpm-s3 -v -b $BUCKET -p $PREFIX --sign elasticsearch-2.0.0-beta1.rpm --visibility public-read
2015-09-01 13:54:36,585 INFO rpmfiles: ['elasticsearch-2.0.0-beta1.rpm']
2015-09-01 13:54:36,587 INFO S3Grabber: s3://XXXX/$PREFIX
2015-09-01 13:54:37,199 INFO FileGrabber: file:///tmp
2015-09-01 13:54:37,199 INFO basepath: /tmp
2015-09-01 13:54:37,211 INFO checking if key exists: $PREFIX/repodata/repomd.xml
2015-09-01 13:54:37,356 INFO Existing repository detected.
2015-09-01 13:54:37,357 INFO rpmfile: /tmp/elasticsearch-2.0.0-beta1.rpm
2015-09-01 13:54:37,357 INFO rpm --resign '/tmp/elasticsearch-2.0.0-beta1.rpm'
2015-09-01 13:54:37,578 INFO fetching: /tmp/elasticsearch-2.0.0-beta1.rpm
2015-09-01 13:54:37,708 INFO urlgrab: /tmp/tmpBlfqOE/cache/s3/repomdsipUfgtmp.xml
2015-09-01 13:54:37,709 INFO checking if key exists: $PREFIX/repodata/repomd.xml
2015-09-01 13:54:37,853 INFO downloading: $PREFIX/repodata/repomd.xml
...