Install semanage command on CentoOS (#554)

CentOS has selinux enabled by default but it hasn't the `semanage` command required to run OpenVPN on another port.
'policycoreutils-python*' match `policycoreutils-python' in CentOS 7 and `policycoreutils-python-utils` in Centos 8.

openvpn-install.sh

@@ -625,7 +625,7 @@ function installOpenVPN () {
 		apt-get install -y openvpn iptables openssl wget ca-certificates curl
 	elif [[ "$OS" = 'centos' ]]; then
 		yum install -y epel-release
-		yum install -y openvpn iptables openssl wget ca-certificates curl tar
+		yum install -y openvpn iptables openssl wget ca-certificates curl tar 'policycoreutils-python*'
 	elif [[ "$OS" = 'amzn' ]]; then
 		amazon-linux-extras install -y epel
 		yum install -y openvpn iptables openssl wget ca-certificates curl