Drop CentOS 5 from launch script tests and upgrade to 6.9

CentOS 5 was declared EOL in March 2017 and yum on longer works
out of the box. 6.9 is the latest release of CentOS 6. Tests for
CentOS 7 have not been added as it uses systemd rather than SysVinit.

Closes spring-projectsgh-9395

Author: wilkinsona

spring-boot-integration-tests/spring-boot-launch-script-tests/src/test/resources/conf/CentOS/5.11-7f8a8084/Dockerfile

@@ -0,0 +1,9 @@
+# CentOS 6.9 from 02/06/2017
+FROM centos@sha256:a23bced61701af9a0a758e94229676d9f09996a3ff0f3d26955b06bac8c282e0
+RUN yum install -y wget && \
+    yum install -y system-config-services && \
+    yum install -y curl && \
+    wget --output-document jdk.rpm \
+        http://cdn.azul.com/zulu/bin/zulu8.21.0.1-jdk8.0.131-linux.x86_64.rpm && \
+    yum --nogpg localinstall -y jdk.rpm && \
+    rm -f jdk.rpm