p2v: Don't run X in non-GUI mode.

Even in non-GUI mode we were starting up the X server in the virt-p2v
ISO.  This is a waste of time and resources, so don't do it.

p2v/launch-virt-p2v.in

@@ -1,6 +1,6 @@
 #!/bin/bash -
 # @configure_input@
-# (C) Copyright 2014 Red Hat Inc.
+# (C) Copyright 2014-2016 Red Hat Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -18,13 +18,22 @@
 
 # This normally runs from systemd which deals with logging.
 
-# To save one script, invoke self again to run the window manager
-# and virt-p2v.
-if [ "$1" = "run" ]; then
-    cd /
-    metacity &
-    nm-applet &
+# Are we running in GUI or non-GUI mode?  This is controlled by the
+# presence of "p2v.server" on the kernel command line.
+cmdline=$(</proc/cmdline)
+if [[ $cmdline == *p2v.server=* ]]; then
+    # Non-GUI mode, don't run X.  Just run virt-p2v directly.
     exec @libexecdir@/virt-p2v --iso
+
 else
-    xinit "$0" run
+    # GUI mode.  Run xinit to start X.  To save one script, we invoke
+    # self again to run the window manager and virt-p2v.
+    if [ "$1" = "run" ]; then
+        cd /
+        metacity &
+        nm-applet &
+        exec @libexecdir@/virt-p2v --iso
+    else
+        xinit "$0" run
+    fi
 fi