Correctly implement what was my intent when removing the HAVE_LIBPCAP

Correctly implement what was my intent when removing the HAVE_LIBPCAP
stuff - arrange that the interface summary list is set, if we've read a
capture file that has interface information, *regardless* of whether we
have libpcap/WinPcap or not.

That means that summary_fill_in() should fill in the interface
information for the summary if there's interface information from the
capture file, and summary_fill_in_capture() - which is called only if
HAVE_LIBPCAP is defined, and can exist only if HAVE_LIBPCAP is defined
(as it takes an argument of a type that's defined only if HAVE_LIBPCAP
is defined) - just fills in interface information from the capture
options and does so only if there's none from the file.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@42873 f5534014-38df-0310-8fa8-9805f1628bb7