Ticket #47391 - deleting and adding userpassword fails to update the password
Bug description: Deleting and adding password operation causes
the crash since once an entry is written to and retrieved from
DB, it does not have unhashed#user#password in the entry any
more. The delete userpassword internally invokes delete unhashed
existed in the entry.
Fix description: This patch adds the stricter check for the NULL
Reviewed by Nathan (Thanks!!)