Travis: Fix OS X build The Travis xcode7.3 image now apparently includes GnuPG 1.4.x by default, so use it instead of installing GnuPG 2. Using GnuPG 2.1.x, the default version in Homebrew as of this writing, is problematic for this reason: https://wiki.archlinux.org/index.php/GnuPG#Unattended_passphrase