merge revision(s) r46778: [Backport #10019]

	* pack.c (encodes): fix buffer overrun by tail_lf.  Thanks to
	  Mamoru Tasaka and Tomas Hoger.  [ruby-core:63604] [Bug #10019]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@46806 b2dd03c8-39d4-4d8f-98ff-823fe69b080e