[Build] Pack swt-download zip after it was signed

Part of
- eclipse-platform/eclipse.platform.releng.aggregator#2189

Author: HannesWell

binaries/pom.xml

@@ -189,7 +189,8 @@
 							</execution>
 							<execution>
 								<id>package-swt-download-zip</id>
-								<phase>package</phase>
+								<!-- Pack this zip after the swt.jar has been signed.-->
+								<phase>verify</phase>
 								<goals>
 									<goal>run</goal>
 								</goals>