Raise on 404 during Webfinger

That's at least readable, return false just causes
silly follow up errors

lib/webfinger.rb

@@ -31,7 +31,9 @@ class Webfinger
     Rails.logger.info("Getting: #{url} for #{account}")
     begin
       res = Faraday.get(url)
-      return false if res.status == 404
+      unless res.success?
+        raise "Failed to fetch #{url}: #{res.status}"
+      end
       res.body
     rescue OpenSSL::SSL::SSLError => e
       Rails.logger.info "Failed to fetch #{url}: SSL setup invalid"

spec/lib/webfinger_spec.rb

@@ -73,13 +73,14 @@ describe Webfinger do
       expect(a_request(:get, redirect_url)).to have_been_made
     end
 
-    it 'returns false on 404' do
+    it 'raises on 404' do
       url ="https://bar.com/.well-known/host-meta"
       stub_request(:get, url).
         to_return(:status => 404, :body => nil)
 
-      expect(finger.get(url)).not_to eq(nil)
-      expect(finger.get(url)).to eq(false)
+      expect {
+        expect(finger.get(url)).to eq(false)
+      }.to raise_error
     end
   end