MT#10261 Conflict with Debian's asterisk package

Our ngcp-asterisk package ships files that are also shipped with
Debian's official asterik (related) packages like
asterisk-modules, so those packages can't be installed at the
same time.

Change-Id: Ia13608081fa0a74db8bbb1a18791378195341ca1

debian/control

@@ -13,6 +13,9 @@ Standards-Version: 3.9.6
 
 Package: ngcp-asterisk
 Architecture: any
+Conflicts: asterisk
+Replaces: asterisk
+Provides: asterisk
 Depends: libmyodbc,
          libpcre3,
          ngcp-prompts,