Fix `RESULT_NOT_PRESENT` on directory tests about foundationdb-rs

[PierreZ]

Incorrect result: 
  rust   - ('tester_output', 'stack', 50, 386) = b'\x01RESULT_NOT_PRESENT\x00'
  python - ('tester_output', 'stack', 50, 386) = b'\x01\x01ERROR\x00\xff\x011020\x00\xff\x00'

Python is failing with 1020 error code: which means Transaction not committed due to conflict with another transaction. Rust has RESULT_NOT_PRESENT, which means everything is fine 🤔

For seed 4275610547, we have:

368. Instruction is COMMIT
369. Instruction is WAIT_FUTURE
370. Instruction is RESET // New transaction
371. Instruction is PUSH
372. Instruction is DIRECTORY_CHANGE
373. Instruction is PUSH
374. Instruction is PUSH
375. Instruction is PUSH
376. Instruction is PUSH
377. Instruction is DIRECTORY_MOVE
378. Instruction is PUSH
379. Instruction is DIRECTORY_CHANGE
380. Instruction is PUSH
381. Instruction is PUSH
382. Instruction is DIRECTORY_OPEN
383. Instruction is PUSH
384. Instruction is PUSH
385. Instruction is DIRECTORY_MOVE_TO_DATABASE
386. Instruction is WAIT_FUTURE
387. Instruction is RESET

All faulty seeds seems to occured before an DIRECTORY_MOVE_TO_DATABASE, which is runned in a standalone transaction.

[PierreZ]

Adding new seed:

+ ./bindings/bindingtester/bindingtester.py --num-ops 1000 --api-version 630 --test-name directory --concurrency 1 rust --no-directory-snapshot-ops --compare python

Creating test at API version 630
Generating directory test at seed 2665254911 with 1000 op(s) and 1 concurrent tester(s)...

Inserting test into database...

Running tester '/home/runner/work/foundationdb-rs/foundationdb-rs/target/debug/bindingtester test_spec 630'...

Reading results from '('tester_output', 'stack')'...
Reading results from '('tester_output', 'directory_log', 'directory')'...
Reading results from '('tester_output', 'directory_log', 'subspace')'...

Inserting test into database...

Running tester 'python /home/runner/work/foundationdb-rs/foundationdb-rs/target/foundationdb_build/foundationdb/bindings/bindingtester/../python/tests/tester.py test_spec 630'...

Reading results from '('tester_output', 'stack')'...
Reading results from '('tester_output', 'directory_log', 'directory')'...
Reading results from '('tester_output', 'directory_log', 'subspace')'...

Comparing results from '('tester_output', 'stack')'...

Incorrect result: 
  rust   - ('tester_output', 'stack', 476, 4361) = b'\x01RESULT_NOT_PRESENT\x00'
  python - ('tester_output', 'stack', 476, 4361) = b'\x01\x01ERROR\x00\xff\x011020\x00\xff\x00'

Comparing results from '('tester_output', 'directory_log', 'directory')'...
Comparing results from '('tester_output', 'directory_log', 'subspace')'...

Test with seed 2665254911 and concurrency 1 had 1 incorrect result(s) and 0 error(s) at API version 630
Completed directory test with random seed 2665254911 and 1000 operations