Fix change of address for ELK plugin

org.polarsys.chess.parent/releng/org.polarsys.chess.target.neon/org.polarsys.chess.target.neon.target

@@ -22,7 +22,7 @@
 <unit id="org.eclipse.elk.feature.feature.group" version="0.4.0"/>
 <unit id="org.eclipse.elk.ui.feature.feature.group" version="0.4.0"/>
 <unit id="org.eclipse.elk.graphviz.feature.feature.group" version="0.4.0"/>
-<repository location="http://build.eclipse.org/modeling/elk/updates/0.4.0/"/>
+<repository location="http://download.eclipse.org/elk/updates/releases/0.4.0/"/>
 </location>
 <location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="planner" includeSource="true" type="InstallableUnit">
 <unit id="org.eclipse.papyrus.sysml.feature.feature.group" version="1.2.0.201703081153"/>