test Release file handling with expired keys

Signing files with expired keys is not as easy as it sounds, so the
framework jumps a few loops to do it, but it might come in handy to have
an expired key around for later tests even if it is not that different
from having no key in regards to APT behaviour.

Git-Dch: Ignore

1 files changed, 0 insertions, 0 deletions

diff --git a/test/integration/rexexpired.pub b/test/integration/rexexpired.pub
new file mode 100644
index 000000000..5ab2e489a
--- /dev/null
+++ b/test/integration/rexexpired.pub