Disable header checker since we have two kinds of headers.

## What changes were proposed in this pull request?
Disables the header checker since we have a different form of the header.

Author: Yin Huai <yhuai@databricks.com>

Closes apache#65 from yhuai/disableHeaderChecker.

scalastyle-config.xml

@@ -46,7 +46,7 @@ This file is divided into 3 sections:
 
   <check level="error" class="org.scalastyle.file.FileTabChecker" enabled="true"></check>
 
-  <check level="error" class="org.scalastyle.file.HeaderMatchesChecker" enabled="true">
+  <check level="error" class="org.scalastyle.file.HeaderMatchesChecker" enabled="false">
     <parameters>
        <parameter name="header"><![CDATA[/*
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