Allow specifying an alternate config file URL on the commandline.

Change-Id: I1b73674c769027cb557b37d3533534f261521106

BUG=chromium-os:781
TEST=manual

Try running recovery.sh with no args. It should try to download the config
file from a default location (which may not actually exist). Then try
running recovery.sh with a URL as a command-line argument. It should fetch
the config file from that location instead.

Review URL: http://codereview.chromium.org/5529006
1 file changed