Qt4 : SPrefs, add a Frame when needed.

(cherry picked from commit 7749487f9a3f90bc43f8c2f33b253590d12eede3)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/ui/sprefs_subtitles.ui

@@ -65,9 +65,6 @@
         <property name="maxVisibleItems" >
          <number>12</number>
         </property>
-        <property name="frame" >
-         <bool>false</bool>
-        </property>
        </widget>
       </item>
       <item row="0" column="1" >