Simplify ./configure logic for telling rpmbuild which GUI(s) we're building.

Rather than checking for all the "--with" arguments just use the "$have_xxx"
variables.

Don't allow rpmbuild's ./configure to decide to build a GUI just because it's
available: make it build only what was ./configure'd.

Change-Id: I68582b4c13da7b52d56591dce68ac426e9f607f1
Reviewed-on: https://code.wireshark.org/review/3958
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>