item_updater: Use Common.FilePath to locate images

The image manager implements the Common.FilePath.Path interface,
make use of it to find the image files instead of hardcoding the
path, since the updater shouldn't know/care where the images are.

Change-Id: Ieb9ad8e393a7f91645631db9f302095eb82d7f61
Signed-off-by: Saqib Khan <khansa@us.ibm.com>
diff --git a/item_updater.hpp b/item_updater.hpp
index 082dbf7..fb8e9df 100644
--- a/item_updater.hpp
+++ b/item_updater.hpp
@@ -70,14 +70,14 @@
         /**
          * @brief Validates the presence of SquashFS iamge in the image dir.
          *
-         * @param[in]  versionId - The software version ID.
+         * @param[in]  filePath  - The path to the image dir.
          * @param[out] result    - ActivationStatus Enum.
          *                         ready if validation was successful.
          *                         invalid if validation fail.
          *                         active if image is the current version.
          *
          */
-        ActivationStatus validateSquashFSImage(const std::string& versionId);
+        ActivationStatus validateSquashFSImage(const std::string& filePath);
 
         /** @brief Persistent sdbusplus DBus bus connection. */
         sdbusplus::bus::bus& bus;