merge revision(s) r46457,r46458: [Backport #9949]

	* lib/net/ftp.rb (gets, readline): read lines without LF properly.
	  [ruby-core:63205] [Bug #9949]

	* test/net/ftp/test_buffered_socket.rb: related test.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@46618 b2dd03c8-39d4-4d8f-98ff-823fe69b080e