test: fix more test defects

test/fixtures/httpoison_mock/https__info.pleroma.site_activity.json

 {
         "@context": "https://www.w3.org/ns/activitystreams",
-        "actor": "https://mastodon.example.org/users/admin",
+        "actor": "http://mastodon.example.org/users/admin",
         "attachment": [],
-        "attributedTo": "https://mastodon.example.org/users/admin",
+        "attributedTo": "http://mastodon.example.org/users/admin",
         "content": "<p>this post was not actually written by Haelwenn</p>",
         "id": "https://info.pleroma.site/activity.json",
         "published": "2018-09-01T22:15:00Z",

test/fixtures/httpoison_mock/https__info.pleroma.site_activity2.json

@@ -2,7 +2,7 @@
         "@context": "https://www.w3.org/ns/activitystreams",
         "attributedTo": "https://info.pleroma.site/actor.json",
         "attachment": [],
-        "actor": "https://mastodon.example.org/users/admin",
+        "actor": "http://mastodon.example.org/users/admin",
         "content": "<p>this post was not actually written by Haelwenn</p>",
         "id": "https://info.pleroma.site/activity2.json",
         "published": "2018-09-01T22:15:00Z",

test/web/activity_pub/transmogrifier_test.exs

@@ -874,8 +874,8 @@ test "it rejects objects with a bogus origin" do
     test "it rejects activities which reference objects with bogus origins" do
       data = %{
         "@context" => "https://www.w3.org/ns/activitystreams",
-        "id" => "https://mastodon.example.org/users/admin/activities/1234",
-        "actor" => "https://mastodon.example.org/users/admin",
+        "id" => "http://mastodon.example.org/users/admin/activities/1234",
+        "actor" => "http://mastodon.example.org/users/admin",
         "to" => ["https://www.w3.org/ns/activitystreams#Public"],
         "object" => "https://info.pleroma.site/activity.json",
         "type" => "Announce"