Establish the working directory for <svninfo> more explicitly; it turns 
out that "." is an unsound default (ant doesn't chdir).

Review by: scottb


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@3674 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/common.ant.xml b/common.ant.xml
index 12b8a3b..4f76a90 100755
--- a/common.ant.xml
+++ b/common.ant.xml
@@ -204,7 +204,7 @@
       <taskdef name="svninfo"
          classname="com.google.gwt.ant.taskdefs.SvnInfo"
          classpath="${gwt.build.lib}/ant-gwt.jar" />
-      <svninfo outputproperty="gwt.svnrev"
+      <svninfo directory="${gwt.root}" outputproperty="gwt.svnrev"
           outputfileproperty="gwt.svnrev.filename" />
       <!-- Generally, filtering requires a sentinel file so that changes to svn rev will
          be noticed as invalidating the previously-generated filter output.  This property