Fix to ubiquity

[Bill Cox]

When installing with screen reader enabled, ubiquity stops talking
about half the time, which is very frustrating for blind users.  I've
been able to get it to work reliably, with only two edits.

First in /usr/bin/ubiquity, change the call from gksu to sudo:

            toexec = ['gksudo', '--preserve-env']
            if desktop:
                toexec.extend(['--desktop', desktop])
            toexec.append('--')

Should be just:

            toexec = ['sudo', '-E']

The second thing is more minor.  If you select a large font, and
install in a VirtualBox machine, with an 800x600 display, then ubquity
hangs when the partitioner screen starts.  This is caused by a
one-line bug in /usr/lib/ubiquity/ubiquity/frontend/gtk_ui.py.  Just
comment out line 554, the last line of win_size_req:

        widget.resize(w, h)

should be:

        #widget.resize(w, h)

Bill