Install amazon jdk and update the sudoer file

- Increase the volume size, default is 8G and too small to install all
required packages
- THe default version of maven in Ubuntu 16.04 is mvn33 but it's mvn36
in Ubuntu 18.04
- We have to setup the JAVA_HOME for mvn36 but we did't do it in our
jobs so all jobs with mvn36 will fail.
- Specify the mvn33

Change-Id: I2560e83d941f6093ee4fe2f1f24bb8b359c2706b
diff --git a/jjb/defaults.yaml b/jjb/defaults.yaml
index b26ea25..d7da8ca 100644
--- a/jjb/defaults.yaml
+++ b/jjb/defaults.yaml
@@ -207,3 +207,7 @@
     # karaf-home
     # Use to grab the logs or onos-diagnostics
     karaf-home: 'apache-karaf-4.2.9'
+
+    # maven version
+    # Have to setup JAVA_HOME correctly if we upgrade to mvn36
+    maven-version: mvn33