pbx_dundi: DUNDi weight parameter not processed correctly

The DUNDi weight field is not always converted from network byte order
to host byte order. This can result in incorrect weight values and
incorrect selection of DUNDi destinations.

ASTERISK-18731 #close
Reported by: Peter Racz
Patches:
	dundi_weight.patch (license #6290) patch uploaded by Peter Racz

Change-Id: Iba3e1a700ff539db57211a7bbc26f7b22ea9a1be