[BZ 1150586] - On first login attempt, LDAP user remains on login screen without any message when - Enable Login Without Roles=No and there is no mapping between JON roles and LDAP groups. - Displaying the generic error message for the first attemnt as well. Also disabling the login button, during the login procedure, because login using LDAP takes some time and we don't want users to click on the button invoking another checks.

(cherry picked from commit adc7dabe5caaf85c807d58ce0cbebd086106d33f)
Signed-off-by: Jirka Kremser <jkremser@redhat.com>