FLUME-2959. Fix issues with flume-checkstyle module

* The lack of a parent POM caused warnings related to UTF-8 encoding
* The XML files should have an ASL 2.0 license header

(Lior Zeno via Mike Percy)

flume-checkstyle/pom.xml

@@ -25,4 +25,10 @@
   <artifactId>flume-checkstyle</artifactId>
   <name>Flume checkstyle project</name>
   <version>1.7.0-SNAPSHOT</version>
+
+  <properties>
+    <!-- Set default encoding to UTF-8 to remove maven complaints -->
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
 </project>

flume-checkstyle/src/main/resources/flume/checkstyle-suppressions.xml

@@ -1,4 +1,23 @@
 <?xml version="1.0" encoding="UTF-8"?>
+<!--
+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.
+-->
+
 <!DOCTYPE suppressions PUBLIC
     "-//Puppy Crawl//DTD Suppressions 1.0//EN"
     "http://www.puppycrawl.com/dtds/suppressions_1_0.dtd">

flume-checkstyle/src/main/resources/flume/checkstyle.xml

@@ -1,4 +1,23 @@
 <?xml version="1.0"?>
+<!--
+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.
+-->
+
 <!DOCTYPE module PUBLIC
           "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
           "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">