nacl_io: Remove the direct syscall intercept for 'remove'

nacl_io: Remove the direct syscall intercept for 'remove'

This is no longer needed as the underlying syscalls
unlink/rmdir and both intercepted at the IRT level.  I
believe this was overlooked when we fixed:
https://code.google.com/p/nativeclient/issues/detail?id=3709

This should fix the recent lua5.2 failures on the
naclports waterfall.

CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_nacl_sdk;tryserver.chromium.mac:mac_nacl_sdk;tryserver.chromium.win:win_nacl_sdk
BUG=487701
Committed: https://crrev.com/c7f1b7b5fa91ad0421e3a358dc7f6bb3aaafbe23
Cr-Commit-Position: refs/heads/master@{#329871}

[Sam Clegg, 2015-05-13 19:12:17]

sbc@chromium.org changed reviewers:
+ binji@chromium.org

[binji, 2015-05-13 21:28:41]

Could you add a link to the CL where unlink and rmdir were added, to the
description above? Was it recent?

otherwise lgtm

[Sam Clegg, 2015-05-13 21:36:52]

On 2015/05/13 21:28:41, binji wrote:
> Could you add a link to the CL where unlink and rmdir were added, to the
> description above? Was it recent?
> 
> otherwise lgtm

I'm not sure when they were added (not recently though) but the bug for getting
them added is here:
https://code.google.com/p/nativeclient/issues/detail?id=3709.   Mentioned this
in the CL description.

[Sam Clegg, 2015-05-14 17:27:59]

The CQ bit was checked by sbc@chromium.org

[commit-bot: I haz the power, 2015-05-14 17:29:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1136953014/20001

[commit-bot: I haz the power, 2015-05-14 17:38:56]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-14 17:40:31]

Patchset 2 (id:??) landed as
https://crrev.com/c7f1b7b5fa91ad0421e3a358dc7f6bb3aaafbe23
Cr-Commit-Position: refs/heads/master@{#329871}