Replace test for session context with userId
Replace test for session context with userId

Recent changes set the context on the session generated during the authentication process.
Previoulsy the test for a null context was a flag to generate the login.  Now test for zero userId, as the user will not be set until after a successful login.

foam-framework/foam2,foam-framework/foam2,foam-framework/foam2,jacksonic/vjlofvhjfgm,foam-framework/foam2,jacksonic/vjlofvhjfgm,jacksonic/vjlofvhjfgm,foam-framework/foam2