Fix NullPointerException if build.properties file doesn't exist in user.home

git-svn-id: https://svn.apache.org/repos/asf/maven/components/trunk@162536 13f79535-47bb-0310-9956-ffa450edef68

maven-mboot/src/main/Bootstrapper.java

@@ -268,21 +268,19 @@ public class Bootstrapper
             // ignore
         }
 
-        return null;
+        return new Properties();
     }
 
     private static Properties loadProperties( InputStream is )
     {
+        Properties properties = new Properties();
+        
         try
         {
-            Properties properties = new Properties();
-
             if ( is != null )
             {
                 properties.load( is );
             }
-
-            return properties;
         }
         catch ( IOException e )
         {
@@ -303,7 +301,7 @@ public class Bootstrapper
             }
         }
 
-        return null;
+        return properties;
     }
 
     static class BootstrapPomParser