merge revision(s) 49034: [Backport #10662]

	* ext/tk/lib/tkextlib/tcllib/plotchart.rb: fix to invoke correct function
	  of tcllib. Patch by @zalt50 [fix GH-787]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@49080 b2dd03c8-39d4-4d8f-98ff-823fe69b080e