Update centos 7 libraries - improve security (#1727)

* Update nccl build version

Update centos 7 docker libraries

Revert "Update nccl build version"

This reverts commit 9b0d3f9.

* test

Author: atalman

conda/Dockerfile

@@ -7,6 +7,7 @@ ENV LANG en_US.UTF-8
 ENV LANGUAGE en_US.UTF-8
 
 ARG DEVTOOLSET_VERSION=9
+RUN yum update -y
 RUN yum install -y wget curl perl util-linux xz bzip2 git patch which unzip
 # Just add everything as a safe.directory for git since these will be used in multiple places with git
 RUN git config --global --add safe.directory '*'