[SPARK-12692][BUILD] Enforce style checking about white space before comma

This is the final PR about SPARK-12692.
We have removed all of white spaces before comma from code so let's enforce style checking.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #10736 from sarutak/SPARK-12692-followup-enforce-checking.

scalastyle-config.xml

@@ -197,6 +197,12 @@ This file is divided into 3 sections:
     </parameters>
   </check>
 
+  <check level="error" class="org.scalastyle.scalariform.DisallowSpaceBeforeTokenChecker" enabled="true">
+    <parameters>
+      <parameter name="tokens">COMMA</parameter>
+    </parameters>
+  </check>
+
   <!-- ================================================================================ -->
   <!--       rules we'd like to enforce, but haven't cleaned up the codebase yet        -->
   <!-- ================================================================================ -->
@@ -217,13 +223,6 @@ This file is divided into 3 sections:
   <!-- Should turn this on, but we have a few places that need to be fixed first -->
   <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker" enabled="false"></check>
 
-  <!-- Should turn this on, but we have a few places that need to be fixed first -->
-  <check level="warning" class="org.scalastyle.scalariform.DisallowSpaceBeforeTokenChecker" enabled="true">
-    <parameters>
-      <parameter name="tokens">COMMA</parameter>
-    </parameters>
-  </check>
-
   <!-- ================================================================================ -->
   <!--                               rules we don't want                                -->
   <!-- ================================================================================ -->