tools: implement blob close

Implement blob close call.

Change-Id: If7c845e1e3b542e6f0253136eb8b6fd40bc96f3d
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/tools/updater.cpp b/tools/updater.cpp
index 6fed1d6..27414c1 100644
--- a/tools/updater.cpp
+++ b/tools/updater.cpp
@@ -92,6 +92,8 @@
         throw ToolException("Failed to send contents of " + imagePath);
     }
 
+    blob->closeBlob(session);
+
     /* Send over the hash contents. */
     /* Trigger the verification. */
     /* Check the verification. */