[SPARK-8064] [BUILD] Follow-up. Undo change from SPARK-9507 that was accidentally reverted

This PR removes the dependency reduced POM hack brought back by #7191

Author: tedyu <yuzhihong@gmail.com>

Closes #7919 from tedyu/master and squashes the following commits:

1bfbd7b [tedyu] [BUILD] Remove dependency reduced POM hack

pom.xml

@@ -179,9 +179,6 @@
     <jsr305.version>1.3.9</jsr305.version>
     <libthrift.version>0.9.2</libthrift.version>
 
-    <!-- For maven shade plugin (see SPARK-8819) -->
-    <create.dependency.reduced.pom>false</create.dependency.reduced.pom>
-
     <test.java.home>${java.home}</test.java.home>
 
     <!--