Fixed compiler warning on SnifferIterator.
Fixed compiler warning on SnifferIterator.

rklabs/libtins,hanw/libtins,mfontanini/libtins,salessandri/libtins,salessandri/libtins,zmb3/libtins,UlfWetzker/libtins,wavelets/libtins,wavelets/libtins,viveks9/decrypt80211,hanw/libtins,capturePointer/libtins,rklabs/libtins,capturePointer/libtins,zmb3/libtins,bowlofstew/libtins,viveks9/decrypt80211,bowlofstew/libtins,mfontanini/libtins,UlfWetzker/libtins