* Implement toString in MockSystemReader and MockConfig
* LocalDiskRefTreeDatabaseTest shall use MockSystemReader
* Ensure LocalDiskRepositoryTestCase#setup fully uses MockSystemReader
* Ensure we use MockSystemReader in tests
* Override FileBasedConfig's save method in MockConfig
* Remove FileBasedConfig.load(boolean) introduced in d45219ba
* Disable debug log for FS in org.eclipse.jgit.test