The current hard-coded value won't work for other distributions not relying on
relying on standard conventions (e.g. nixos...).
This keeps the original behavior and only allow to diverge basesd on the
environment variable BIN_CASSANDRA (don't like the name, just kept the naming
logic from LOG_CASSANDRA).[1]
This also fixes an issue on log path inexistence which raises.
Currently trying to run this with my box and this prevents it.
[1] I do not like the name much, I just kept the naming convention from the
LOG_CASSANDRA variable. Although, it's probably fine as it's only for tests.