init: Gracefully handle missing browser

Gerrit might be installed on a headless server that does not have a
browser installed, or has a browser binary but no X11 server is
configured in the environment.  Handle these installations by telling
the user the browser could not be opened and request opening the URL.

Bug: issue 1898
Change-Id: I17c47ac8eb390a5d89db52ad023612b8738dde7d
1 file changed