linux: show the manpage on -h or --help
linux: show the manpage on -h or --help

Review URL: http://codereview.chromium.org/160026

git-svn-id: http://src.chromium.org/svn/trunk/src@21450 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 59c1ec62871aa0ab92e31b603f7347f40e273ed3
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser