An old patch designed to fix http://bugme.osdl.org/show_bug.cgi?id=4497,
"getdents gives empty/random result upon signal".
If smbfs's readdir() is interupted by a signal, smb_readdir() failed to
noticed that and proceeded to treat the unread-into page as valid directory
contents. Fix that up by handling the -ERESTARTSYS.
Thanks to Stian Skjelstad for reporting and testing.