Dockerfile: Update centos devtoolset-6 to devtoolset-7 (#9990)

since former is no longer available in the upstream repo

src/tools/docker/centos6/Dockerfile

@@ -10,13 +10,11 @@ RUN yum makecache && \
 
 # install all software we need
 RUN yum makecache && \
-    yum -y install python-pip && \
-    yum -y install python-devel python-psutil python-setuptools && \
+    yum -y install python-pip python-devel python-psutil python-setuptools && \
     yum -y install apr-devel bzip2-devel expat-devel libcurl-devel && \
     yum -y install libevent-devel libuuid-devel libxml2-devel libyaml-devel libzstd-devel && \
     yum -y install openssl-devel pam-devel readline-devel snappy-devel && \
     yum -y install apache-ivy libicu perl-ExtUtils-Embed perl-Env perl-JSON && \
-    pip install psi lockfile && \
     yum clean all
 
 # setup ssh configuration
@@ -35,9 +33,10 @@ RUN ssh-keygen -t rsa -N "" -f /root/.ssh/id_rsa && \
 
 # newer version of gcc and run environment for gpdb
 RUN yum -y install centos-release-scl && \
-    yum -y install --nogpgcheck devtoolset-6-gcc devtoolset-6-gcc-c++ && yum clean all && \
+    yum -y install --nogpgcheck devtoolset-7-gcc devtoolset-7-gcc-c++ && yum clean all && \
+    pip --no-cache-dir install psi lockfile && \
     ln -s /usr/bin/cmake3 /usr/bin/cmake && \
-    echo -e 'source /opt/rh/devtoolset-6/enable' >> /opt/gcc_env.sh && \
+    echo -e 'source /opt/rh/devtoolset-7/enable' >> /opt/gcc_env.sh && \
     echo -e 'source /opt/gcc_env.sh' >> /root/.bashrc && \
     echo -e '#!/bin/sh' >> /etc/profile.d/jdk_home.sh && \
     echo -e 'export JAVA_HOME=/etc/alternatives/java_sdk' >> /etc/profile.d/jdk_home.sh && \

src/tools/docker/centos7/Dockerfile

@@ -10,13 +10,11 @@ RUN yum makecache && \
 
 # install all software we need
 RUN yum makecache && \
-    yum -y install python2-pip && \
-    yum -y install python-devel python-psutil python-setuptools && \
+    yum -y install python2-pip python-devel python-psutil python-setuptools && \
     yum -y install apr-devel bzip2-devel expat-devel libcurl-devel && \
     yum -y install libevent-devel libuuid-devel libxml2-devel libyaml-devel libzstd-devel && \
     yum -y install openssl-devel pam-devel readline-devel snappy-devel && \
     yum -y install apache-ivy libicu perl-ExtUtils-Embed perl-Env perl-JSON && \
-    pip install psi lockfile && \
     yum clean all
 
 # setup ssh configuration
@@ -35,9 +33,10 @@ RUN ssh-keygen -t rsa -N "" -f /root/.ssh/id_rsa && \
 
 # newer version of gcc and run environment for gpdb
 RUN yum -y install centos-release-scl && \
-    yum -y install --nogpgcheck devtoolset-6-gcc devtoolset-6-gcc-c++ && yum clean all && \
+    yum -y install --nogpgcheck devtoolset-7-gcc devtoolset-7-gcc-c++ && yum clean all && \
+    pip --no-cache-dir install psi lockfile && \
     ln -s /usr/bin/cmake3 /usr/bin/cmake && \
-    echo -e 'source /opt/rh/devtoolset-6/enable' >> /opt/gcc_env.sh && \
+    echo -e 'source /opt/rh/devtoolset-7/enable' >> /opt/gcc_env.sh && \
     echo -e 'source /opt/gcc_env.sh' >> /root/.bashrc && \
     echo -e '#!/bin/sh' >> /etc/profile.d/jdk_home.sh && \
     echo -e 'export JAVA_HOME=/etc/alternatives/java_sdk' >> /etc/profile.d/jdk_home.sh && \