Revert "Remove gwt.logging.popupHandler"

This reverts commit f15d4aaa6bee4715c3dce221775c039efdd0c28f.
Released GWT still needs this property.
Google will have to filter it out in the build process.

Change-Id: Ie487bd32d741c42bd5f79d2c80ebe8976e667200

gerrit-gwtui/src/main/java/com/google/gerrit/GerritGwtUI.gwt.xml

diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/GerritGwtUI.gwt.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/GerritGwtUI.gwt.xml
index fd717ee..b8102ec 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/GerritGwtUI.gwt.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/GerritGwtUI.gwt.xml
@@ -39,6 +39,7 @@
   <add-linker name='xsiframe'/>
 
   <set-property name='gwt.logging.logLevel' value='SEVERE'/>
+  <set-property name='gwt.logging.popupHandler' value='DISABLED'/>
 
   <entry-point class='com.google.gerrit.client.Gerrit'/>
 </module>