Update documentation for "COMMIT=false"

Update documentation for "COMMIT=false".

The meaning of "COMMIT=false" was changed in https://code.google.com/p/chromium/issues/detail?id=470609.
I have also updated the corresponding Chromium documentation in https://sites.google.com/a/chromium.org/dev/developers/testing/commit-queue

BUG=skia:
NOTRY=true
DOCS_PREVIEW= https://skia.org/?cl=1107343004

Committed: https://skia.googlesource.com/skia/+/38620209ca67535686c6b62a2185254ef119196a

[rmistry, 2015-04-28 16:44:07]

rmistry@google.com changed reviewers:
+ hcm@google.com, jcgregorio@google.com

[hcm, 2015-04-28 17:15:19]

One nit, then lgtm

https://codereview.chromium.org/1107343004/diff/1/site/dev/contrib/cqkeywords.md
File site/dev/contrib/cqkeywords.md (right):

https://codereview.chromium.org/1107343004/diff/1/site/dev/contrib/cqkeywords...
site/dev/contrib/cqkeywords.md:10: To dry run through the CQ please use
Rietveld's [dry
run](https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/G5-X0_tfmok)
feature.
"To dry run" -> "To do a dry run"

[rmistry, 2015-04-28 17:27:36]

https://codereview.chromium.org/1107343004/diff/1/site/dev/contrib/cqkeywords.md
File site/dev/contrib/cqkeywords.md (right):

https://codereview.chromium.org/1107343004/diff/1/site/dev/contrib/cqkeywords...
site/dev/contrib/cqkeywords.md:10: To dry run through the CQ please use
Rietveld's [dry
run](https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/G5-X0_tfmok)
feature.
On 2015/04/28 17:15:19, hcm wrote:
> "To dry run" -> "To do a dry run"

Done.

[rmistry, 2015-04-28 17:27:54]

The CQ bit was checked by rmistry@google.com

[rmistry, 2015-04-28 17:27:55]

The patchset sent to the CQ was uploaded after l-g-t-m from hcm@google.com
Link to the patchset: https://codereview.chromium.org/1107343004/#ps20001
(title: "Address comment")

[commit-bot: I haz the power, 2015-04-28 17:28:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1107343004/20001

[commit-bot: I haz the power, 2015-04-28 17:28:16]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/38620209ca67535686c6b62a2185254ef119196a