Remove sudoers hack

base/singularity:2.5

@@ -2,8 +2,7 @@ FROM debian:stretch
   MAINTAINER Tamas Gal <tgal@km3net.de>
 
   RUN apt-get update -qq && apt-get install -y wget bzip2 python-pip git
-  RUN apt-get install -y build-essential squashfs-tools libtool autotools-dev libarchive-dev automake autoconf uuid-dev libssl-dev sudo
+  RUN apt-get install -y build-essential squashfs-tools libtool autotools-dev libarchive-dev automake autoconf uuid-dev libssl-dev
 
   RUN pip install sregistry[all]
-  RUN sed -i -e 's/^Defaults\tsecure_path.*$//' /etc/sudoers
   RUN cd /tmp && git clone -b vault/release-2.5 https://www.github.com/sylabs/singularity.git && cd singularity && ./autogen.sh && ./configure --prefix=/usr/local && make && make install