Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Set version to 2.15.8-SNAPSHOT
  ElasticTestUtils: Factor common code out of ElasticReindexIT/ElasticIndexIT
  Add support for Elasticsearch 6.5.0
  Add Marco Miller as a developer in pom.xml files
  Set version to 2.14.17

Change-Id: I0bb655abd6a158f09f670ad65cd37f70479fe483
diff --git a/tools/maven/gerrit-extension-api_pom.xml b/tools/maven/gerrit-extension-api_pom.xml
index 50072a5..872b09b 100644
--- a/tools/maven/gerrit-extension-api_pom.xml
+++ b/tools/maven/gerrit-extension-api_pom.xml
@@ -56,6 +56,9 @@
       <name>Luca Milanesio</name>
     </developer>
     <developer>
+      <name>Marco Miller</name>
+    </developer>
+    <developer>
       <name>Martin Fick</name>
     </developer>
     <developer>