MT#9261 Build-Depend on either libtiff5-dev or libtiff4-dev

This provides support for building on Debian/jessie.

debian/control

@@ -2,8 +2,7 @@ Source: ngcp-iaxmodem
 Section: utils
 Priority: extra
 Maintainer: Sipwise Development Team <support@sipwise.com>
-Build-Depends: debhelper (>= 5),
-               libtiff4-dev
+Build-Depends: debhelper (>= 5), libtiff5-dev | libtiff4-dev
 Standards-Version: 3.9.5
 Homepage: http://iaxmodem.sourceforge.net/