admin_password in neutron conf needs to be configured to be a secret
admin_password in neutron conf needs to be configured to be a secret

Exploiters should be able to encrypt admin_password. Also, admin_password
is printed in plain text in neutron and infoblox ipam agent log files.
Making admin_password config secret, will fix these problems.

Change-Id: I3e3ee39fffd338e4ec78a1c49867bbc5bef3268c
Closes-Bug:#1551901

openstack/networking-infoblox,openstack/networking-infoblox