Separate the promiscuous mode, "Update list of packets in real time",

Separate the promiscuous mode, "Update list of packets in real time",
and "Automatic scrolling in live capture" options from the preference
settings for them, so that the preference settings affect the initial
values of those options, but changing those values in a capture don't
affect the preferences, and don't automatically get saved when you save
the preferences.

If we're building without libpcap, don't have an "Automatic scrolling in
live capture" option anywhere.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@4514 f5534014-38df-0310-8fa8-9805f1628bb7