Fix eunit test on OTP18

[lrascao]

OTP18 changed the output failed assertion string
from assertEqual_failed to assertEqual

[ferd]

If I get the tests right, this works in old versions because we match on a partial string and assertEqual still matches assertEqual_failed? This does seem a bit brittle (it would match on assertEqual_success) but fine by me.

[lrascao]

luckily there's no assertEqual_success but i see your point, the actual string that is being returned is:
**error:{assertEqual_failed,[{module,myapp_mymod3},
{line,8},
{expression,"false"},
{expected,true},
{value,false}]}

ideally we should be able to parse the whole string into an erlang term and match that, much safer that way

[ferd]

Agreed. for the time being this is fine, though.