set update site url from property


git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@819296 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/sigil/sigil-defaults.properties b/sigil/sigil-defaults.properties
index b6c3581..21440ee 100644
--- a/sigil/sigil-defaults.properties
+++ b/sigil/sigil-defaults.properties
@@ -4,7 +4,7 @@
 version: ${buildVersion:-0.9.0.SNAPSHOT}
 
 # Default bundle headers
-header;update-site: http://people.apache.org/~dsavage/sigil/updates-site-snapshot
+header;update-site: ${update.site:-${.}/site}
 header;Bundle-Category: development
 header;Bundle-ContactAddress: http://felix.apache.org
 header;Bundle-Vendor: The Apache Software Foundation