XUI does not correctly set link to return to login page in CDSSO deployments

XUI does not correctly set the "Return to Login Page" link on the log out page in CDSSO deployments.

Steps to quickly check the behavior (without setting up a CDSSO environment):

1. Access to:
   http://openam.example.com:8080/openam/cdcservlet?goto=http%3A%2F%2Fapp.exmple.co.jp%3A80%2Findex.html&RequestID=1472631989655&MajorVersion=1&MinorVersion=0&ProviderID=http%3A%2F%2Fapp.exmple.co.jp%3A80%2Famagent&IssueInstant=2016-08-31T08%3A26%3A29Z
2. Login as demo.
   -> #403 is shown.
3. Access to:
   http://openam.example.com:8080/openam/
   -> End user page is shown.
4. Click the logout button.
5. Check the "Return to Login Page" link.
   When using classic UI:
   http://openam.example.com:8080/openam/UI/Login?goto=%2Fopenam%2Fcdcservlet%3FTARGET%3Dhttp%253A%252F%252Fapp.exmple.co.jp%253A80%252Findex.html%26RequestID%3D1472631989655%26MajorVersion%3D1%26MinorVersion%3D0%26ProviderID%3Dhttp%253A%252F%252Fapp.exmple.co.jp%253A80%252Famagent%26IssueInstant%3D2016-08-31T08%253A26%253A29Z&&MajorVersion=1&ProviderID=http%3A%2F%2Fapp.exmple.co.jp%3A80%2Famagent&RequestID=1472631989655&MinorVersion=0&IssueInstant=2016-08-31T08%3A26%3A29Z&gx_charset=UTF-8&gx_charset=UTF-8
   When using XUI:
   http://openam.example.com:8080/openam/XUI/#login/&goto=/openam/cdcservlet?TARGET=http://app.exmple.co.jp:80/index.html
6. Click the link.
   -> Login page is shown.
7. Login as demo again.
   When using classic UI:
   -> Redirect to the "goto" page.
   When using XUI:
   -> #501 is shown.