tests: Make tests more robust.
* tests/openpgp/defs.scm (have-opt-always-trust): Execute in empty ephemeral home directory. This prevents gpg from picking up the configuration from the current gnupghome (if any). * tests/migrations/common.scm (untar-armored): Likewise.
- Signed-off-by: Justus Winter <justus@g10code.com>