see URL.

The svn credentials worked - but then password was changed for the user (but
hudson wasn't informed). Hudson never complained about the password rejected.

Turning up the logging on svn kit revealed the actual issue (although hudson
never caught this)

steps to reproduce

1) setup svn server with ssh access
2) create job with scm pointing to svn+ssh:///
3) enter credentials
4) do a build
5) change password for ssh user on svn box (but not hudson)
6) try another build
7) create a new build pointing to the same project (scm urm) as in 2)

expected results
HUdson complains about lack of credentials - or invalid password

actual results
Hudson doesn't complain - all builds come to a standstill.
the new job sits with "A SCM change triggered this job"