Spottes by:	dridi

the shared memory segment could have gone away, simply
ignore the segment in that case.

Fixes #2411

about varnishlog(1).

And some whitespace cleanup.

At present mostly consisting of XXX's.

Fixes #2416

Closes #2421

To be revisited post release.

References #2421

Refs da91fec9

decode() and transcode() now have an optional parameter length;
if length > 0, decode that many characters from the encoded string.

References #2421

This is mostly a mechanical patch.