loci: remove *_new_from_message

These functions were never used. How would you know what type of message it was
without parsing it first? The test is changed to use
of_object_new_from_message, which is what actual clients use.
loci: factor out of_object_attach

This code was duplicated by bind and list operations, and will be used for
match deserialization..
loci: remove a malloc/free from parsing of_match_t

The code was allocating an of_wire_buffer_t on the heap (through some
indirection) and then immediately freeing it. We can just use the parent
object's wire buffer instead.
loci: fix memory leak in locitest
Merge into master from pull request #283:
remove dead code and speed up match deserialization (https://github.com/floodlight/loxigen/pull/283)