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
diff --git a/phosphor-ldap-config/ldap_config.hpp b/phosphor-ldap-config/ldap_config.hpp
index 9cf59f7..220677c 100644
--- a/phosphor-ldap-config/ldap_config.hpp
+++ b/phosphor-ldap-config/ldap_config.hpp
@@ -280,6 +280,8 @@
     void certificateInstalled(sdbusplus::message::message& msg);
     sdbusplus::bus::match_t certificateInstalledSignal;
 
+    sdbusplus::bus::match_t cacertificateInstalledSignal;
+
     /** @brief React to certificate changed signal
      *  @param[in] msg - sdbusplus message
      */