gir: start fixing OSTree.Sign

I don't think the SignDummy and SignEd25519 types even need to be
visible. The explicit dummy_* and ed25519_* don't need to be visible
either, I suspect.

rust-bindings/rust/conf/ostree.toml

@@ -47,9 +47,6 @@ generate = [
     "OSTree.RepoPullFlags",
     "OSTree.RepoRemoteChange",
     "OSTree.RepoResolveRevExtFlags",
-    "OSTree.Sign",
-    "OSTree.SignDummy",
-    "OSTree.SignEd25519",
     "OSTree.SePolicy",
     "OSTree.SePolicyRestoreconFlags",
     "OSTree.StaticDeltaGenerateOpt",
@@ -187,6 +184,13 @@ status = "generate"
 init_function_expression = "|_ptr| ()"
 clear_function_expression = "|_ptr| ()"
 
+[[object]]
+name = "OSTree.Sign"
+status = "generate"
+    [[object.function]]
+    pattern = "dummy_.+|ed25519_.+"
+    ignore = true
+
 [[object]]
 name = "OSTree.*"
 status = "generate"