sync: Point dev channel sync engines to clients4.google.com/chrome-sync/dev
sync: Point dev channel sync engines to clients4.google.com/chrome-sync/dev

BUG=none
TEST=create unofficial build or build with version string modifier equal to "dev".
start syncing.


Review URL: http://codereview.chromium.org/2847006

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@49865 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser