Ticket 48975- Disabling CLEAR password storage scheme will
crash server when setting a password
Bug Description: If the CLEAR password storage scheme plugin is disabled, and a
userpassword is set, the server crashes. This is because we
expect this plugin to be enabled when working with the unhashed
password.
Fix Description: Always check if the password scheme, returned by pw_val2scheme(),
is NULL before dereferencing it. If it is NULL treat it as a
clear text password.
Valgrind: Passed
https://fedorahosted.org/389/ticket/48975
Reviewed by: nhosoi(Thanks!)
(cherry picked from commit 52230585a1191bf1e747780b592f291d652e26dd)