Fix problem with invalid MD5 passwords.

Fix a problem where specifying a wrong password for a user that has his password stored as Apache MD5 would result in an IllegalArgumentException.
User IStoredSettings instead of Gitblit. Changed realmFile variable name.

Implemented two suggestions:
Renamed the variable realmFile to htpasswdFile.
Store the IStoredSettings passed into setup() and use that instead of Gitblit in most places.