Fix TestSnappyCodec failure

Summary: Making TestSnappyCodec not fail if the native Snappy library is not available.

Test Plan: ant clean && ant -Dtestcase=TestSnappyCodec test-core

Reviewers: pritam, weiyan, ramkumar

Reviewed By: pritam

Task ID: 1196650

src/core/org/apache/hadoop/io/compress/CodecUnavailableException.java

@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.hadoop.io.compress;
+
+/** 
+ * Thrown when a compression codec is unavailable, e.g. because the native library is not 
+ * provided.
+ */
+public class CodecUnavailableException extends IllegalStateException {
+
+  private static final long serialVersionUID = 1L;
+
+  public CodecUnavailableException() {
+    super();
+  }
+
+  public CodecUnavailableException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
+  public CodecUnavailableException(String s) {
+    super(s);
+  }
+
+  public CodecUnavailableException(Throwable cause) {
+    super(cause);
+  }
+
+}