pyloxi: move pack_list to generic_util

For consistency with unpack_list.
diff --git a/py_gen/templates/generic_util.py b/py_gen/templates/generic_util.py
index 99840ec..039d82a 100644
--- a/py_gen/templates/generic_util.py
+++ b/py_gen/templates/generic_util.py
@@ -35,6 +35,9 @@
 import loxi
 import struct
 
+def pack_list(values):
+    return "".join([x.pack() for x in values])
+
 def unpack_list(reader, deserializer):
     """
     The deserializer function should take an OFReader and return the new object.
diff --git a/py_gen/templates/util.py b/py_gen/templates/util.py
index 9c9ccc1..8ad246a 100644
--- a/py_gen/templates/util.py
+++ b/py_gen/templates/util.py
@@ -151,9 +151,6 @@
     return reader.read("!Q")[0]
 :: #endif
 
-def pack_list(values):
-    return "".join([x.pack() for x in values])
-
 MASK64 = (1 << 64) - 1
 
 def pack_bitmap_128(value):