Let apt-get select the right version

This assumes apt-get update has been run

docs/rtd_upgrade.sh

@@ -30,20 +30,21 @@ perl --version
 mkdir packages
 cd packages
 # List of extra packages we need
-echo http://archive.ubuntu.com/ubuntu/pool/main/libd/libdbi-perl/libdbi-perl_1.640-1_amd64.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libd/libdbd-sqlite3-perl/libdbd-sqlite3-perl_1.56-1_amd64.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libj/libjson-xs-perl/libjson-xs-perl_3.040-1_amd64.deb \
-     http://archive.ubuntu.com/ubuntu/pool/main/libj/libjson-perl/libjson-perl_2.90-1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libc/libcommon-sense-perl/libcommon-sense-perl_3.74-2build2_amd64.deb \
-     http://archive.ubuntu.com/ubuntu/pool/main/libt/libtypes-serialiser-perl/libtypes-serialiser-perl_1.0-1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libx/libxml-xpath-perl/libxml-xpath-perl_1.30-1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libp/libparse-recdescent-perl/libparse-recdescent-perl_1.967013+dfsg-1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/main/libi/libipc-run-perl/libipc-run-perl_0.94-1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/main/libi/libio-pty-perl/libio-pty-perl_1.08-1.1build1_amd64.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libg/libgraphviz-perl/libgraphviz-perl_2.20-1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/d/doxypy/doxypy_0.4.2-1.1_all.deb \
-     http://archive.ubuntu.com/ubuntu/pool/universe/libp/libproc-daemon-perl/libproc-daemon-perl_0.23-1_all.deb \
-| xargs -n 1 curl -O
+apt-get download \
+     libdbi-perl \
+     libdbd-sqlite3-perl \
+     libjson-xs-perl \
+     libjson-perl \
+     libcommon-sense-perl \
+     libtypes-serialiser-perl \
+     libxml-xpath-perl \
+     libparse-recdescent-perl \
+     libipc-run-perl \
+     libio-pty-perl \
+     libgraphviz-perl \
+     doxypy \
+     libproc-daemon-perl \
+
 
 mkdir ../root
 for i in *.deb; do dpkg -x "$i" ../root/; done