Second attempt to fix builds

Modify sources list *before* running update

cedar-14.dockerfile

@@ -1,8 +1,8 @@
 FROM heroku/cedar:14
 MAINTAINER Akash Manohar
 
-RUN apt-get update
 RUN sed -i '/^deb http:\/\/apt\.postgresql\.org\/*/d' /etc/apt/sources.list
+RUN apt-get update
 RUN apt-get install -y curl wget ca-certificates
 RUN apt-get install -y gcc g++
 RUN apt-get install -y make automake autoconf