fix ChangelogEntryTest.testChangelogEntryRendering

[escitalopram]

which failed previously because of wrong cache contents
left by some prior test method

[Jotschi]

The test is not failing for me (JDK 1.8.x). Could you please elaborate or check your clone?

[escitalopram]

It fails for me out of the box with maven-3.3.9 and openjdk 1.8.0_121

When you execute ChangelogSiteGeneratorTest#testGCNChangelogRendering and ChangelogEntryTest#testChangelogEntryRendering in sequence from the same classloader, the latter will fail.

mvn test "-Dtest=ChangelogSiteGeneratorTest,ChangelogEntryTest"

produces this for me:

java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
        at java.util.ArrayList.rangeCheck(ArrayList.java:653)
        at java.util.ArrayList.get(ArrayList.java:429)
        at com.gentics.changelogmanager.changelog.ChangelogEntryTest.testChangelogEntryRendering(ChangelogEntryTest.java:24)

[CLAassistant]

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