Reflect the reality of the database

**Why**:
The db/schema.rb and migrations got out of sync.

**How**:
Update the db/schema.rb to reflect what the migrations
build.

app/services/ocsp_service.rb

@@ -31,9 +31,9 @@ def build_request
   end
 
   def ocsp_url_for_subject
-    authority.ocsp_url.presence || begin
+    authority.ocsp_http_url.presence || begin
       uri = subject.ocsp_http_url
-      authority.ocsp_url = uri
+      authority.ocsp_http_url = uri
       authority.save!
       uri
     end

db/schema.rb

@@ -23,7 +23,7 @@
     t.datetime "valid_not_after", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.string "ocsp_url"
+    t.string "ocsp_http_url"
     t.index ["key"], name: "index_certificate_authorities_on_key", unique: true
   end