Tests broke due to c4934ca [1].

If promises are used, you needn't pass `done` as parameter of
the callback in.

[1]: c4934ca#diff-0a6449ecfa8b9e3d807f53dde24eca71R66

When stopping an IPFS node it returns an error. The error message
depends on the environment. In Browsers it might also return
`Failed to fetch` or `XHR error`. Hence removing the specific
error check as it would fail for Browsers.

Instead check if the node is an go-ipfs one.

Without increasing the timeout this test fails on Jenkins way
too often.

The DHT doesn't work well with a low number of peers (the more
the better). Hence increase it to 5 peers. This should make
the test more reliable.

The DHT works best with >- 20 nodes, this means that the tests
might fail (but it passes most of the time). Hence skip the query
test before the timeout is reached.