Fixed deleting last build

And remove an useless test scenario.
No, please see this commit https://github.com/Bishop/integrity/commit/f795ecc363b6e31f09456abed41bdfd2ced88fbc.

This test is very old. Before you separate handle last_build and previous_builds. So this test check: if previous_builds not displays if there is only one build. Really it checks line, removed here: https://github.com/Bishop/integrity/commit/f795ecc363b6e31f09456abed41bdfd2ced88fbc#diff-f0e2d2c04d2c212ee671e03a1c836020L20
:smile: