Put the code to handle NDS ping replies and NDS replies into routines of

Put the code to handle NDS ping replies and NDS replies into routines of
their own.

Do the tapping as early as possible, so it's done even if exceptions are
thrown - and do it regardless of whether the tree argument is null or
not, because a tap might be run without generating protocol trees.

Generate the expert info regardless of whether the tree arugment is null
or not, as that's also used with taps.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@16303 f5534014-38df-0310-8fa8-9805f1628bb7