Application fails on oauth2 callback

[norbertpotocki]

Steps to reproduce:

• clone repository (with my patch applied: Dependencies problem #2)
• run "mvn tomcat:run"
• browse to: http://localhost:8080/spring-social-foursquare-example/signin
• click "sign in with foursquare" button
• accept connection request on foursquare page

Result:

• you are redirected to: http://localhost:8080/spring-social-foursquare-example/signin/foursquare?code=xxx...
• there's an 400 http error:

HTTP Status 400 -
type Status report
message
description The request sent by the client was syntactically incorrect ().
Apache Tomcat/6.0.29

Expected:

• redirect to some correct result page