item_updater: Add version dbus object.

Implementing the Version object under item_updater helps
to retain the version of the active images after the bmc
is rebooted and the image_dir no longer holds version file.

Change-Id: I55349bbc62b212b4e034239f4f6743129c8b1070
Signed-off-by: Saqib Khan <khansa@us.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index 7d65c7a..261cd6b 100755
--- a/Makefile.am
+++ b/Makefile.am
@@ -37,6 +37,7 @@
 
 phosphor_image_updater_SOURCES = \
 	activation.cpp \
+	version.cpp \
 	item_updater.cpp \
 	item_updater_main.cpp