Updated logstash from 1.4.1 to 1.4.2

Just a general update to the latest stable version.

Version Changelog from 1.4.1 to 1.4.2:
```
1.4.2 (June 24, 2014)
  # general
  - fixed path issues when invoking bin/logstash outside its home directory

  # input
  - bugfix: generator: fixed stdin option support
  - bugfix: file: fixed debian 7 path issue

  # codecs
  - improvement: stdin/tcp: automatically select json_line and line codecs with the tcp and stdin streaming imputs
  - improvement: collectd: add support for NaN values

  # outputs
  - improvement: nagios_nsca: fix external command invocation to avoid shell escaping
```