Always request detached metadata for commit objects, even if we already
have the commit object. This ensures we fetch any post facto detached
metadata updates such as new GPG signatures.
https://bugzilla.gnome.org/748220
This uses gpgv for verification against DATADIR/ostree/pubring.gpg by
default. The keyring can be overridden by specifying OSTREE_GPG_HOME.
Add a unit test for commit signing with gpg key and verifying on pull;
to implement this we ship a test GPG key generated with no password
for Ostree Tester <test@test.com>.
Change all of the existing tests to disable GPG verification.
Matthew Barnes
Giuseppe Scrivano
Jeremy Whiting