Refactor buck external dependencies

Change-Id: Ia4b99493407eb7d4e893804cba6b944f758f085e
diff --git a/apps/restconf/utils/BUCK b/apps/restconf/utils/BUCK
index 760082d..8ebc904 100644
--- a/apps/restconf/utils/BUCK
+++ b/apps/restconf/utils/BUCK
@@ -1,5 +1,6 @@
 COMPILE_DEPS = [
     '//lib:CORE_DEPS',
+    '//lib:JACKSON',
     '//lib:jersey-client',
     '//lib:jersey-server',
     '//lib:javax.ws.rs-api',