Update developers based on gerritcodereview's list

Accordingly with [1], add the missing core maintainers as developers.

Remove Ole Rehmsen, accordingly with [1,2].

[1] https://www.gerritcodereview.com/members.html#maintainers
[2] https://www.gerritcodereview.com/members.html#former-maintainers

Change-Id: I3bff1b86a9c7729f0b9b88818c045cb5e21939ff
diff --git a/tools/maven/gerrit-war_pom.xml b/tools/maven/gerrit-war_pom.xml
index ffb1dae..948056b 100644
--- a/tools/maven/gerrit-war_pom.xml
+++ b/tools/maven/gerrit-war_pom.xml
@@ -35,15 +35,24 @@
       <name>David Pursehouse</name>
     </developer>
     <developer>
+      <name>Dmitrii Filippov</name>
+    </developer>
+    <developer>
       <name>Edwin Kempin</name>
     </developer>
     <developer>
+      <name>Gal Paikin</name>
+    </developer>
+    <developer>
       <name>Han-Wen Nienhuys</name>
     </developer>
     <developer>
       <name>Jacek Centkowski</name>
     </developer>
     <developer>
+      <name>Joerg Zieren</name>
+    </developer>
+    <developer>
       <name>Luca Milanesio</name>
     </developer>
     <developer>
@@ -56,7 +65,10 @@
       <name>Matthias Sohn</name>
     </developer>
     <developer>
-      <name>Ole Rehmsen</name>
+      <name>Milutin Kristofic</name>
+    </developer>
+    <developer>
+      <name>Nasser Grainawi</name>
     </developer>
     <developer>
       <name>Patrick Hiesel</name>