phosphor-ldap-conf: handle "InterfaceAdded" signal on the ca-cert object

When ever a new ca-cert file is installed/changed(re-installed),
the certificate manager sends a Signal, which is caught by the
phosphor-user-manager and the nslcd deamon will be restarted with
the appropriate ca-certfile.

TestedBy:
Installed a new ca-certificate using busctl command, and verified if the
phosphor-user-manager captured the InterfaceAdded signal there by updating
the nslcd configuration accordingly.

Signed-off-by: manojkiraneda <manojkiran.eda@gmail.com>
Change-Id: Iffc9b70435d819f6bdaee57970edc65f555ff42d
2 files changed