remove duplicate declaration of gson

Change-Id: I8661dbf6b6b63c9b3a79fa099fd79c15a2a587d3
diff --git a/lib/BUCK b/lib/BUCK
index e3b6a78..de17152 100644
--- a/lib/BUCK
+++ b/lib/BUCK
@@ -1,4 +1,4 @@
-# ***** This file was auto-generated at Tue, 8 Aug 2017 17:39:19 GMT. Do not edit this file manually. *****
+# ***** This file was auto-generated at Fri, 18 Aug 2017 16:55:01 GMT. Do not edit this file manually. *****
 # ***** Use onos-lib-gen *****
 
 pass_thru_pom(