[LyX/2.0.x] Rerun makeindex if all nomencl entries have been removed (#8905)

[Juergen Spitzmueller]

commit 8431f55f7378cce800b880f9a4b644e8ce71b63f
Merge: b6b1ab8 a09bdca
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Mon Feb 10 07:47:47 2014 +0100

    Rerun makeindex if all nomencl entries have been removed (#8905)