fixed findbugs warning: File.exists() and File.delete() return value was not checked

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@930810 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/dependencymanager/annotation/src/main/java/org/apache/felix/dm/annotation/plugin/mvn/AnnotationMojo.java b/dependencymanager/annotation/src/main/java/org/apache/felix/dm/annotation/plugin/mvn/AnnotationMojo.java
index caf9dc2..81ba6f4 100644
--- a/dependencymanager/annotation/src/main/java/org/apache/felix/dm/annotation/plugin/mvn/AnnotationMojo.java
+++ b/dependencymanager/annotation/src/main/java/org/apache/felix/dm/annotation/plugin/mvn/AnnotationMojo.java
@@ -186,7 +186,9 @@
         finally
         {
             jar.close();
-            tmp.delete();
+            if (tmp.exists() && ! tmp.delete()) {
+                throw new MojoExecutionException("Could not remove " + tmp);
+            }
         }
     }
 }