In addition to fitting better (brute library is the verb, creds library
is the noun), this will allow creds.lua to use creds.Account internally
where necessary (see subsequent commits)
Also change old references to string argument "OPEN" into
creds.State.VALID.
Apache JServer Protocol requests. [Patrik Karlsson]
o [NSE] Added the script ajp-brute, which enables password brute force auditing
against the Apache JServ Protocol service. [Patrik Karlsson]