csv.rb: use Array#to_h

* lib/csv.rb (CSV::Row#to_hash): use Array#to_h

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59426 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/csv.rb

@@ -532,8 +532,7 @@ class CSV
     # order and clobbers duplicate fields.
     #
     def to_hash
-      # flatten just one level of the internal Array
-      Hash[*@row.inject(Array.new) { |ary, pair| ary.push(*pair) }]
+      @row.to_h
     end
 
     #