Manage certificates created by applications

Added watch on certificate path to watch on certificates
created/updated by apps.

As part of watch notification, create new D-Bus new certificate
and for existing D-Bus object update the properties.

Tested:
Test case 1
1) Ensure no certificate is present
2) Restart certificate service
3) Restart bmcweb service
4) Verified that certificate object is created for the
   self-signed certificate created by bmcweb.

Test case 2
1) After a certificate is present
2) Modify the bmcweb certificate by replacing it
   with a valid certificate manually.
3) Verified that certificate manager is notified
and certificate objects properties are updated.

Test case 3
1) Upload CSR based certificate file
2) Verified that private key is appended to the file

Test case 4
1) Create a dummy file in certificate folder
2) Verified that notification is received and file is ignored

Test case 5
1) Verified install, replace, generate csr.

Change-Id: I7d1e3624958e4b68e5ba7bc6150c19b11fca501a
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index e498a16..ff20da0 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -32,3 +32,4 @@
 certs_manager_test_LDADD = $(top_builddir)/certs_manager.o
 certs_manager_test_LDADD += $(top_builddir)/certificate.o
 certs_manager_test_LDADD += $(top_builddir)/csr.o
+certs_manager_test_LDADD += $(top_builddir)/watch.o