Description: The freenx package ships a script (/opt/NX/bin/nxdialog) which is called to do things like display the dialog asking whether the user wants to suspend or terminate the session when the server receives the Ctrl-Alt-T combo. This script attempts to launch the popup using the xdialog, dialog, or xmessage binaries. If none of these are installed, there is no error message; the dialog box just never shows up.

We should make the freenx package depend on one of the three dialog utilities that this script attempts to use. I'll suggest xdialog since that's the one the script checks for first, and the one that I have installed and verified as resolving the issue.

Additional info:
* package version(s) = 0.7.3-6
* config and/or log files etc. = N/A

Steps to reproduce:
1. Install freenx on a system without the xdialog, dialog, or xorg-xmessage packages installed.
2. Connect to this system using nxclient from another machine.
3. Attempt to close the client or Ctrl-Alt-T. Notice that nothing happens and the client remains open. (Normal expectation: a dialog pops up prompting if you wish to suspend or terminate the session. The client closes after you make a selection).