make injected login modules return false on success

[danibusu]

• login method now returns false on success, in order to not interfere with the outcome of the whole login process
• update timeout login module to not clean up the session timeout from the login result because, as a consequence of the previous change, the commit() method will call the logout0() method and not commit0(), disabling the session timeout everytime
• updated tests

[dpwspoon]

LGTM, waiting for travis to pass