(bug 19751) Filesystem is now checked during image undeletion

(bug 19751) Filesystem is now checked during image undeletion
* FSRepo::storeBatch() now does an sha1 check unless SKIP_VALIDATION flag is set
* Introduced Status::$success in addition to Status::$successcount
** FSRepo::storeBatch() now logs success/failure in this variable
* LocalFileRestoreBatch now aborts on failure in FSRepo::storeBatch() and cleans up the already copied files
** Introduced FSRepo::cleanupBatch() for this purpose
* SpecialUndelete now aborts if LocalFile::restore() gives a fatal