[Libguestfs] [PATCH v3] p2v: Allow virt-p2v to be built with Gtk 2 or 3.

[Richard W.M. Jones]

This version of the Gtk 2/3 patch gets alignment and padding mostly
right.  I still can't work out how to vertically align labels in the
middle of a cell in a GtkGrid.  The GtkTextView in the final dialog is
still broken.

Rich.