[ci] Stop symlinking python36 to python3 on CentOS

CentOS recently started to provide python3 by default obsoleted python36. Our
manual hack broke the test suite and is no longer required.

Author: D4N

ci/install_dependencies.sh

@@ -50,7 +50,7 @@ case "$distro_id" in
         curl https://copr.fedorainfracloud.org/coprs/defolos/devel/repo/epel-7/defolos-devel-epel-7.repo > /etc/yum.repos.d/_copr_defolos-devel.repo
         yum clean all
         yum -y install devtoolset-3-gcc-c++ devtoolset-3-gcc-c++ devtoolset-3-binutils clang cmake3 make ccache \
-            expat-devel zlib-devel libssh-devel libcurl-devel gtest-devel gmock-devel which python36 dos2unix
+            expat-devel zlib-devel libssh-devel libcurl-devel gtest-devel gmock-devel which python3 dos2unix
         echo source /opt/rh/devtoolset-3/enable >> ~/.bash_profile
         echo export CCACHE_PATH=$HOME/bin:$PATH >> ~/.bash_profile
         mkdir ~/bin
@@ -63,13 +63,7 @@ EOF
 /usr/bin/clang --gcc-toolchain=/opt/rh/devtoolset-3/root/ \$@
 EOF
         chmod +x ~/bin/clang*
-        # symlink up to date versions of python & cmake to 'default' names
-        if [ ! -e /usr/bin/python3 ]; then
-            ln -s /usr/bin/python36 /usr/bin/python3
-        elif [ -L /usr/bin/python3 ]; then
-            rm /usr/bin/python3
-            ln -s /usr/bin/python36 /usr/bin/python3
-        fi
+        # symlink up to date version of cmake to the 'default' name
         mv /bin/cmake /bin/.cmake.old
         ln -s /bin/cmake3 /bin/cmake
         ;;