Update jenkins-test-harness to 2.27 to pick up fix.
<!-- Should only need to override these if using timestamped snapshots: -->
<jenkins-core.version>${jenkins.version}</jenkins-core.version>
<jenkins-war.version>${jenkins.version}</jenkins-war.version>
- <jenkins-test-harness.version>2.23</jenkins-test-harness.version>
+ <jenkins-test-harness.version>2.27</jenkins-test-harness.version>
<hpi-plugin.version>2.0</hpi-plugin.version>
<stapler-plugin.version>1.17</stapler-plugin.version>
<java.level>7</java.level>
