fix incorrect equals when cpString is null

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1615435 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/maven/plugin/dependency/fromDependencies/BuildClasspathMojo.java b/src/main/java/org/apache/maven/plugin/dependency/fromDependencies/BuildClasspathMojo.java
index 1e30d6c..f575457 100644
--- a/src/main/java/org/apache/maven/plugin/dependency/fromDependencies/BuildClasspathMojo.java
+++ b/src/main/java/org/apache/maven/plugin/dependency/fromDependencies/BuildClasspathMojo.java
@@ -329,7 +329,7 @@
         try
         {
             String oldCp = readClasspathFile();
-            return (cpString.equals(oldCp) || ( cpString != null && cpString.equals( oldCp ) ) );
+            return ( cpString == null ? oldCp == null : cpString.equals( oldCp ) );
         }
         catch ( Exception ex )
         {