Make warning about unset properties only appear at VERBOSE level.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@268456 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/ProjectHelper.java

@@ -641,7 +641,7 @@ public class ProjectHelper {
                 }
                 String n=value.substring( pos+2, endName );
                 if (!keys.containsKey(n)) {
-                    project.log("Property ${" + n + "} has not been set", Project.MSG_WARN);
+                    project.log("Property ${" + n + "} has not been set", Project.MSG_VERBOSE);
                 }
                 
                 String v = (keys.containsKey(n)) ? (String) keys.get(n) : "${"+n+"}";