Make logic explicit in template.

I see this warning when I render this template:
modules/ssh/templates/sshd_config.erb:3: warning: string literal in condition
Im not sure if this effects all versions of ruby or what. I think that this was your intension. Let me know if this isn't want you wanted here.

On:
ubuntu
ruby 1.9.3p0
puppet 3.4.3
Merge pull request #28 from cruisibesarescondev/patch-1

Make logic explicit in template.