f3probe: allow errno == ENODATA when calling read(2)

The errno ENODATA is not documented in the manual, but according
to the comment the following comment, it behaves like EIO.

#82 (comment)

libdevs.c

@@ -415,7 +415,7 @@ static int read_all(int fd, char *buf, size_t count)
 		if (rc < 0) {
 			if (errno == EINTR)
 				continue;
-			assert(errno == EIO);
+			assert(errno == EIO || errno == ENODATA);
 			return - errno;
 		}
 		assert(rc != 0); /* We should never hit the end of the file. */