Typo

(cherry picked from commit 3478d9eab8cffd80570e26b0479455fcdeb73d35)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/qt4.cpp

@@ -106,7 +106,7 @@ static void ShowDialog   ( intf_thread_t *, int, int, intf_dialog_args_t * );
                              " This option only works with Windows and " \
                              "X11 with composite extensions." )
 
-#define OPACITY_FS_TEXT N_( "Fullscreen controller opacity opacity between 0.1 and 1" )
+#define OPACITY_FS_TEXT N_( "Fullscreen controller opacity between 0.1 and 1" )
 #define OPACITY_FS_LONGTEXT N_( "Sets the fullscreen controller opacity between 0.1 and 1 " \
                              "for main interface, playlist and extended panel."\
                              " This option only works with Windows and " \