Add version property to integration tests to servers know if it is a Vaadin 6 or 7 test

Change-Id: Id16238351289ce8df81bed3cd364cc4aa8bba95c

uitest/integration_base_files/base.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0"?>
 <project name="test" basedir=".">
     <property file="deploy.properties" />
+    <property name="vaadin.major.7" value="1" />
     <property name="lock" value="deploy/lock.file" />
     <property name="deployDir" value="deploy/${server}" />
     <property name="serverPort" value="8080" />