Update entrypoint for centos6 build

Author: renecannao

docker/images/proxysql/rhel-compliant/rhel6/entrypoint/entrypoint.bash

@@ -4,14 +4,6 @@ set -eu
 echo "==> Build environment:"
 env
 
-echo "==> Dirty patching to ensure OS deps are installed"
-
-yum -y install gnutls-devel libtool || true
-yum -y install epel-release
-sed -i "s/mirrorlist=https/mirrorlist=http/" /etc/yum.repos.d/epel.repo
-yum -y install http://repo.okay.com.mx/centos/6/x86_64/release/okay-release-1-1.noarch.rpm
-yum -y upgrade automake autoconf
-
 echo "==> Cleaning"
 # Delete package if exists
 rm -f /opt/proxysql/binaries/proxysql-${CURVER}-1-${PKG_RELEASE}.x86_64.rpm || true