[reva] locking support

[butonic]

-> running `locks':
 0. init.................. pass
 1. begin................. pass
 2. options............... pass
 3. precond............... pass
 4. init_locks............ pass
 5. put................... pass
 6. lock_excl............. pass
 7. discover.............. pass
 8. refresh............... pass
 9. notowner_modify....... FAIL (DELETE of locked resource should fail)
10. notowner_lock......... FAIL (UNLOCK with bogus lock token)
11. owner_modify.......... FAIL (PROPPATCH on locked resouce on `/remote.php/webdav/litmus/lockme': 501 Not Implemented)
12. notowner_modify....... FAIL (DELETE of locked resource should fail)
13. notowner_lock......... FAIL (UNLOCK with bogus lock token)
14. copy.................. FAIL (could not COPY locked resource:
404 Not Found)
15. cond_put.............. SKIPPED
16. fail_cond_put......... SKIPPED
17. cond_put_with_not..... pass
18. cond_put_corrupt_token FAIL (conditional PUT with invalid lock-token should fail: 204 No Content)
19. complex_cond_put...... pass
20. unlock................ pass
21. fail_cond_put_unlocked FAIL (conditional PUT with invalid lock-token should fail: 204 No Content)
22. lock_shared........... FAIL (requested lockscope not satisfied!  got shared, wanted exclusive)
23. notowner_modify....... SKIPPED
24. notowner_lock......... SKIPPED
25. owner_modify.......... SKIPPED
26. double_sharedlock..... SKIPPED
27. notowner_modify....... SKIPPED
28. notowner_lock......... SKIPPED
29. unlock................ SKIPPED
30. prep_collection....... pass
31. lock_collection....... pass
32. owner_modify.......... FAIL (PROPPATCH on locked resouce on `/remote.php/webdav/litmus/lockcoll/lockme.txt': 501 Not Implemented)
33. notowner_modify....... FAIL (DELETE of locked resource should fail)
34. refresh............... pass
35. indirect_refresh...... pass
36. unlock................ pass
37. unmapped_lock......... WARNING: LOCK on unmapped url returned 200 not 201 (RFC4918:S7.3)
    ...................... pass (with 1 warning)
38. unlock................ pass
39. finish................ pass
-> 9 tests were skipped.
<- summary for `locks': of 31 tests run: 20 passed, 11 failed. 64.5%

needs cs3 api changes, unless we want to hack our way around it

[refs]

move to reva?