Fix instructions to generate .DEPS.git

Fix instructions to generate .DEPS.git

Adds the -w argument in the instructions in DEPS.
See chromium-dev thread http://goo.gl/sVP94W.

BUG=
NOTRY=true
TBR=brettw@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269435

[Primiano Tucci (use gerrit), 2014-05-08 21:27:04]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2014-05-08 21:30:33]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/primiano@chromium.org/279583002/1

[brettw, 2014-05-08 21:41:01]

lgtm

https://codereview.chromium.org/279583002/diff/1/DEPS
File DEPS (right):

https://codereview.chromium.org/279583002/diff/1/DEPS#newcode7
DEPS:7: #   python tools/deps2git/deps2git.py -o .DEPS.git -w /path/chrome #
(w/o src)
"/path/chrome" is a bit confusing to me 

Maybe write:
#   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
# where <gcliendir> is the absolute path to the directory containing the
.gclient file (the parent of "src").

[Primiano Tucci (use gerrit), 2014-05-08 21:47:35]

The CQ bit was unchecked by primiano@chromium.org

[Primiano Tucci (use gerrit), 2014-05-08 21:51:13]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2014-05-08 21:53:17]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/primiano@chromium.org/279583002/20001

[commit-bot: I haz the power, 2014-05-09 22:19:31]

Change committed as 269435