Applied the fix suggested by Mirko Friedenhagen in #IO-100. This isn't something that it's easy to write a unit test for, but it is very easy to write a platform dependent test and show that the new code correctly throws an exception for '/etc/passwd'

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/io/trunk@482411 13f79535-47bb-0310-9956-ffa450edef68

Author: hen

src/java/org/apache/commons/io/FileUtils.java

@@ -142,7 +142,10 @@ public static void touch(File file) throws IOException {
             OutputStream out = new FileOutputStream(file);
             IOUtils.closeQuietly(out);
         }
-        file.setLastModified(System.currentTimeMillis());
+        boolean success = file.setLastModified(System.currentTimeMillis());
+        if(!success) {
+            throw new IOException("Unable to set the last modification time for " + file);
+        }
     }
 
     //-----------------------------------------------------------------------