eva: 0.2.5 -> 0.2.7

Please note that this update is pinned to a git rev as there's no tag
for 0.2.7, but a release on crates.io[1], this is reported in the repo[2].

Also added a patch to fix the test-suite[3].

[1] https://crates.io/crates/eva/0.2.7
[2] https://github.com/NerdyPepper/eva/issues/32
[3] https://github.com/NerdyPepper/eva/pull/33