include dirmngr as a dependency

now that gnupg 2.1 requires it for keyserver operation, we need to add
it as a hard dependency because otherwise key fetching fails, and
that's a key component of monkeysign

debian/control

@@ -23,6 +23,7 @@ Depends: ${shlibs:Depends}
        , python-pkg-resources
        , gnupg
        , gnupg-agent
+       , dirmngr
 Recommends: python-qrencode
           , python-gtk2
           , python-zbar