Increase max cmd line length for RestartJob. Current cmd line length is 515 chars.
Increase max cmd line length for RestartJob.
Current cmd line length is 515 chars.

BUG=chromium-os:13078
TEST=manual. "Create account" link launched in Guest mode fine.

Review URL: http://codereview.chromium.org/6685118

Change-Id: I6796b6343b4cda9fdcc92eb19f1a03d18da4a000

joshfire/chromiumos-platform-login_manager,chadversary/chromiumos.platform.login_manager,chadversary/chromiumos.platform.login_manager,joshfire/chromiumos-platform-login_manager,chadversary/chromiumos.platform.login_manager,joshfire/chromiumos-platform-login_manager