[NaCl SDK] nacl_io: ignore mode bits when creating files.

[NaCl SDK] nacl_io: ignore mode bits when creating files.

It is legal to create a file with mode bits that conflict with the open flags,
e.g.:

   open("foo", O_WRONLY | O_CREAT, 0444);

BUG=none
R=sbc@chromium.org

Committed: https://crrev.com/f5f1c81f5f1b55516d36e40288db0e7d62e88585
Cr-Commit-Position: refs/heads/master@{#299919}

[Sam Clegg, 2014-10-14 16:53:00]

Interesting.  Did not know that.  LGTM.

[binji, 2014-10-16 17:02:52]

The CQ bit was checked by binji@chromium.org

[commit-bot: I haz the power, 2014-10-16 17:03:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/659513002/1

[commit-bot: I haz the power, 2014-10-16 17:49:45]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-16 17:50:49]

Patchset 1 (id:??) landed as
https://crrev.com/f5f1c81f5f1b55516d36e40288db0e7d62e88585
Cr-Commit-Position: refs/heads/master@{#299919}