Add a catch for the following null pointer exception that Neil got while running synchro tests on his machine.
The root cause for this exception requires a deeper investigation.

    [testng] Failed Test: 
org.opends.server.synchronization.changelog.ChangelogTest#changelogChaining
    [testng] Failure Cause:  java.lang.NullPointerException
    [testng] 
org.opends.server.synchronization.changelog.Changelog.shutdown(Changelog.java:566)
    [testng] 
org.opends.server.synchronization.changelog.ChangelogTest.changelogChaining(ChangelogTest.java:726)