Refactor buck external dependencies

Change-Id: Ia4b99493407eb7d4e893804cba6b944f758f085e
diff --git a/protocols/openflow/api/BUCK b/protocols/openflow/api/BUCK
index c371a02..266a1fc 100644
--- a/protocols/openflow/api/BUCK
+++ b/protocols/openflow/api/BUCK
@@ -1,5 +1,6 @@
 COMPILE_DEPS = [
     '//lib:CORE_DEPS',
+    '//lib:NETTY',
     '//lib:openflowj',
     '//lib:netty-transport',
 ]