people don't blindly insert the old address into new dissectors, which
is probably how it got into the dissectors being fixed here.
svn path=/trunk/; revision=3348
source name from "pi.compat_top_tvb", which should always be set to the
tvbuff that refers to the data that old-style dissectors are currently
working on.
Arrange that it be so set in those dissectors that create alternate data
sources and call other dissectors, and also arrange that "pi.len" and
"pi.captured_len" be set appropriately as well.
svn path=/trunk/; revision=3286