6588160: jaas krb5 client leaks OS-level UDP sockets (all platforms)

Reviewed-by: jccollet, chegar

src/share/classes/sun/security/krb5/KrbKdcReq.java

@@ -274,6 +274,7 @@ public abstract class KrbKdcReq {
                                + ",Attempt =" + i
                                + ", #bytes=" + obuf.length);
                     }
+                    try {
                         /*
                          * Send the data to the kdc.
                          */
@@ -296,6 +297,9 @@ public abstract class KrbKdcReq {
                                 throw se;
                             }
                         }
+                    } finally {
+                        kdcClient.close();
+                    }
                 }
             }
             return ibuf;

src/share/classes/sun/security/krb5/internal/UDPClient.java

@@ -93,4 +93,7 @@ public class UDPClient {
         return data;
     }
 
+    public void close() {
+        dgSocket.close();
+    }
 }