resuce when environ has invalid byte sequence.

This Pr is for this:
```
ArgumentError: invalid byte sequence in UTF-8
	from /usr/lib64/ruby/gems/2.1.0/gems/sys-proctable-0.9.4-universal-linux/lib/linux/sys/proctable.rb:134:in `split'
	from /usr/lib64/ruby/gems/2.1.0/gems/sys-proctable-0.9.4-universal-linux/lib/linux/sys/proctable.rb:134:in `block in ps'
	from /usr/lib64/ruby/gems/2.1.0/gems/sys-proctable-0.9.4-universal-linux/lib/linux/sys/proctable.rb:110:in `foreach'
	from /usr/lib64/ruby/gems/2.1.0/gems/sys-proctable-0.9.4-universal-linux/lib/linux/sys/proctable.rb:110:in `ps'
	from (irb):3
	from /usr/bin/irb:11:in `<main>'
```

The app that is causing it to freak out is dovecot in case you wanted to know.