MT#17699 Bump Standards-Version to 3.9.7

No further changes required to update to Debian Policy 3.9.7[.0]

Change-Id: I8e2b9237b505c39b915e3fc850ae241e03ad2f52

debian/control

@@ -5,7 +5,7 @@ Maintainer: Sipwise Development Team <support@sipwise.com>
 Build-Depends: debhelper (>= 5),
                libglib2.0-dev,
                libmysqlclient15-dev
-Standards-Version: 3.9.6
+Standards-Version: 3.9.7
 Homepage: http://sipwise.com/
 
 Package: ngcp-mediator