Qfs test script: fix typo in variable name.
Qfs client lib: change read only open to force update the file attribute cache to ensure that for at least several seconds KfsClinet::Stat(const char* path_name) (stat() equivalent) returns the same file attribute as KfsClient::Stat(int fd) (fstat() equivalent), assuming no other calls (rename or delete for example) would result in the cache invalidation. The intention is to help to make code that uses hadoop api that has no fstat() and no lseek(SEEK_END) equivalents handle more reliably file rename in place performed by other qfs "clients".