Remove 'release/' from checksum file

[diraol]

By having <sha256> release/goss... this prevents from automating the
check between the sha and the file, since sha256sum will try to find the
goss file within the release directory and usually, while automating goss
installation, we have them both in the same path and run the check from
this path, not from outside a release directory.

Relates to: #447

[aelsabbahy]

I like the idea, I wonder if it can be implemented without running sed on the Sha file

[aelsabbahy]

Travis-CI failed :( seems there's something in the makefile that's broken.

[diraol]

Oh man, sorry, I didn't received Travis-ci failed build feedback.

I guess it was missing a Tab character, I've edited it, let's see. :)

[diraol]

Ok, all good now, I guess :)

[aelsabbahy]

#585 conflicted with this in a major way (re-wrote a lot of this code).

I ended up creating #592 to fix this.

Thank you for taking the time to implement this, sorry it ended up conflicting with a much bigger change.

[diraol]

No problem at all, glad to help :)