MT#17231 debian/control: add asterisk-modules to conflicts

We are getting when migrating from ngcp-asterisk to stock asterisk on mr4.3

> dpkg: error processing archive /var/cache/apt/archives/asterisk-modules_1%3a11.13.1~dfsg-2+b1_amd64.deb (--unpack):
> trying to overwrite '/usr/lib/asterisk/modules/app_echo.so', which is also in package ngcp-asterisk 1.4.24.1+ngcp.9+0~mr4.3.0.0+0~20151216080251.270+jessie~1.gbp484dd0

Change-Id: Ie9b73444b2026b82892388299b25a1678551d516

debian/control

@@ -13,7 +13,8 @@ Standards-Version: 3.9.6
 
 Package: ngcp-asterisk
 Architecture: any
-Conflicts: asterisk
+Conflicts: asterisk,
+           asterisk-modules
 Replaces: asterisk
 Provides: asterisk
 Depends: libmyodbc,