Merge pull request #5241 from Supermathie/s_encode

single_sign_on: encode the payload with strict_encode64 which doesn't add extraneous newlines

lib/single_sign_on.rb

@@ -78,7 +78,7 @@ class SingleSignOn
   end
 
   def payload
-    payload = Base64.encode64(unsigned_payload)
+    payload = Base64.strict_encode64(unsigned_payload)
     "sso=#{CGI::escape(payload)}&sig=#{sign(payload)}"
   end