Currently openstacklib only accepts password_hash instead of password
for db credentials, thus we should implement hashing process in each
modules, with including puppet-mysql and puppet-postgresql.
This patch migrates that hash generation to puppet-openstacklib, so
that all logics related to db is gathered in one module.
In addition, because postgresql_password function was deprecated in
favor of postgresql::postgresql_password in puppet-postgresql
6.5.0[1], this patch also deals with that deprecation.
[1] 700d2c5bb5
Change-Id: I898d31e88188bfd3476412a37f48fc918122a98a
e4b68e9ad6