Restart gpg-agent instead of just shutting down all GnuPG daemons
Restarting the gpg-agent explicitly after shutting down the GnuPG daemons
is much safer than relying on the agent being started on demand.
(cherry picked from commit bc51bb7f15af3304692440bbfe29325335eb391b)
- GnuPG-bug-id: T7021