Simplify configuration of Apt source repositories

Instead of trying to add the "deb-src" entries to sources.list for the
current distro, we can look at the existing file to determine the
lines that we should add.

This is simpler and more reliable when Debian restructures their
repositories.

build.sh

@@ -40,19 +40,12 @@ version="1.9.0"
 revision="2${lsb_release_name}~uninett"
 
 
-cat >> /etc/apt/sources.list << EOF
-deb-src http://cdn-fastly.deb.debian.org/debian ${lsb_release_name} main
-deb-src http://cdn-fastly.deb.debian.org/debian ${lsb_release_name}-updates main
-deb-src http://security.debian.org ${lsb_release_name}-security main
-EOF
-
-if test ${lsb_release_name} != "bullseye"
-  then
-    sed -i "s/${lsb_release_name}-security/${lsb_release_name}\/updates/" /etc/apt/sources.list
-fi
-
+# Add source repositories. We will need them to download the original source
+# package for radsecproxy.
+sed -n 's@^deb @deb-src @p' /etc/apt/sources.list > /etc/apt/sources.list.d/sources.list
 apt-get update
 
+
 RADSECPROXY_URL="https://github.com/${package}/${package}"
 RADSECPROXY_SRCURL="${RADSECPROXY_URL}/releases/download/${version}/${package}-${version}.tar.gz"
 curl --silent -o "${package}"_"${version}".orig.tar.gz -L "${RADSECPROXY_SRCURL}"