[ethereal-dev] Checked in change to re-enable capture filters with wiretap

[guy@xxxxxxxxxx (Guy Harris)]

"wiretap" has no filters to use when reading a capture file, so it's
reasonable to disable those filters when building Ethereal with
"wiretap", but, even when built with "wiretap", Ethereal uses "libpcap"
to capture packets, so there's no need to disable the capture filters...

...and, in fact, given that disabling the filter sets it to
"<unavailable>", which "libpcap"s compiler rejects, and given that
disabling it doesn't let you correct it, and thus (at least when I tried
it) disabling it prevents you from capturing packets, one shouldn't
disable the capture filters.

I've checked in a change to "capture.c" to turn the capture filter back
on when using "wiretap".