FileInputStream.java (close): Check if the fd is valid.

* java/io/FileInputStream.java (close): Check if the fd is valid.
	* java/io/RandomAccessFile.java (close): Ditto.
	* java/net/PlainDatagramSocketImpl.java (close): Ditto.
	* java/net/PlainSocketImpl.java (close): Ditto.

From-SVN: r38131

libjava/java/io/RandomAccessFile.java

@@ -24,7 +24,8 @@ public class RandomAccessFile implements DataOutput, DataInput
 {
   public void close () throws IOException
   {
-    fd.close();
+    if (fd.valid())
+      fd.close();
   }
 
   public final FileDescriptor getFD () throws IOException