Remove trailing spaces

[stuart-c]

To fix #205

[hairyhenderson]

@stuart-c this is OK in theory, but is it necessary to address #205? Can't you simply remove the \n like mentioned in #205 (comment) ?

[stuart-c]

The reason I went with this approach is:

• Newlines aren't valid at the end of most if not all the various env vars we are using (e.g. CONSUL_VAULT_MOUNT)
• Many tools will add newlines to the end of files (e.g. echo '' > file will unless you remember to add -n)
• Having a newline in the produced nonce file is nice (e.g. cat works without having to remember to add the newline on the command line)

So this change would fix the nonce problem, but also fix possible future issues where people are using say VAULT_SECRET_ID_FILE with a file with trailing newline.

[hairyhenderson]

Thanks for the explanation, @stuart-c. That makes sense to me!