Revert "Explicitly create tags table with InnoDB engine"

This reverts commit b8b72e51af.

extensions/tags/migrations/2015_02_24_000000_create_tags_table.php

@@ -33,8 +33,6 @@ return [
             $table->integer('discussions_count')->unsigned()->default(0);
             $table->dateTime('last_time')->nullable();
             $table->integer('last_discussion_id')->unsigned()->nullable();
-
-            $table->engine = 'InnoDB';
         });
 
         $schema->getConnection()->table('tags')->insert([