Update repo url (#682)

Author: Tulio Garcia

vaadin-spreadsheet/pom.xml

@@ -418,7 +418,7 @@
         <repository>
             <id>vaadin-addons</id>
             <name>Vaadin add-ons repository</name>
-            <url>http://vaadin.com/nexus/content/repositories/vaadin-addons</url>
+            <url>http://tools.vaadin.com/nexus/content/repositories/vaadin-addons</url>
         </repository>
     </distributionManagement>