Revert "Revert "Revert "Revert "Move 'Swap volume buttons' option to 'Buttons' menu""""

This reverts commit e5955a0dbfd119a1607225a297e9e2c39a21c2fe.
ButtonSettings.java: fix compile error

Change-Id: Iaeec32e6f374cc2777a8966e3cbfb0d14766b212
(cherry picked from commit 245a897e3c404db2394e9975b503406bb88ff112)