Avoid NPE when defaultVal is also null (13 times at JMeter startup)
Avoid NPE when defaultVal is also null (13 times at JMeter startup)

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1294527 13f79535-47bb-0310-9956-ffa450edef68

Former-commit-id: c738b79725b9860e7bdfbd0db150f6ace6eb350e
apache/jmeter,apache/jmeter,apache/jmeter,etnetera/jmeter,etnetera/jmeter,etnetera/jmeter,benbenw/jmeter,ham1/jmeter,apache/jmeter,etnetera/jmeter,etnetera/jmeter,ham1/jmeter,benbenw/jmeter,ham1/jmeter,ham1/jmeter,ham1/jmeter,benbenw/jmeter,benbenw/jmeter,apache/jmeter