Login: don't fail with DB constraint violations when the application ID is not set in FxContext

git-svn-id: http://svn.flexive.org/repository/flexive/trunk@2929 d35d4baa-7912-0410-b0ae-edacad209e15
Updated to XStream 1.4.7

git-svn-id: http://svn.flexive.org/repository/flexive/trunk@2930 d35d4baa-7912-0410-b0ae-edacad209e15