CAS-1293: SimpleTestUsernamePasswordAuthenticationHandler is not visible

SimpleTestUsernamePasswordAuthenticationHandler has been moved to the
'test' tree of cas-core module and therefore not visible to any module
classpath any more. This commit fixes x509 module's WiringTests
by replacing SimpleTestUsernamePasswordAuthenticationHandler with
AcceptUsersAuthenticationHandler.
test scope for cas-server-support-generic module
Merge pull request #227 from Unicon/CAS-1293

CAS-1293: SimpleTestUsernamePasswordAuthenticationHandler is not visible