[NGRINDER-414] SVN error during access

The reason of this issue is: if one user accessed one repository, and
tried to access another's repository(provided he has access rights),
there will be access error, but there is no imput box to input new user
name and password.
Added a realm and filter for SVN access. If one user try to access
another user's repository, the filter will throw an authentication
error. Then user can input new name and password to access.
Merge branch 'master' of https://github.com/nhnopensource/ngrinder