Add unit test for certificate install

Change-Id: I25700842983be152edc18f78912a917220867b0b
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index a597c38..7ff740a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,3 +21,5 @@
 phosphor_certificate_manager_CXXFLAGS = \
 	$(SYSTEMD_CFLAGS) \
 	$(PHOSPHOR_DBUS_INTERFACES_CFLAGS)
+
+SUBDIRS = . test