inspec-compliance: fix upload of profiles

[srenatus]

Fixes #572.

The bug was a change in Inspec::Profile.archive.

Removed some caveats that seemed to be possible reasons but were not:

• Use Dir::Tmpname.create when we only need a temp name, not a file.
• Use binary mode for reading the tarball, because it's binary data.
• Don't set content-type header twice.

[arlimus]

Awesome improvements on top of the fix! 👍
Cheers @srenatus

[aaronlippold]

👍