[LyX/master] Do not invoke AM_NLS twice.

[Jean-Marc Lasgouttes]

commit d1b866c99b64c5dc29fc2afda63163e05ed89adb
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Mon Nov 23 11:53:46 2015 +0100

    Do not invoke AM_NLS twice.

diff --git a/configure.ac b/configure.ac
index f62a8d3..d82fcaa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -170,13 +170,13 @@ if echo $prefix |grep ' ' >/dev/null 2>/dev/null ; then
 fi
 
 ### Setup po directory
-AM_PO_SUBDIRS
 AM_NLS
 if test $USE_NLS = "yes" ; then
   AC_DEFINE(ENABLE_NLS, 1,
     [Define to 1 if translation of program messages to the user's native 
language
    is requested.])dnl'
 fi
+AM_PO_SUBDIRS
 
 # some standard header files
 AC_HEADER_MAJOR