merge revision(s) r46649: [Backport #10005]

	* node.c (dump_node): handle nd_value == (NODE *)-1 to mean this
	  keyword argument is required


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@47035 b2dd03c8-39d4-4d8f-98ff-823fe69b080e