Teach cache-url to handle file:// URIs.

We can now support file:// URIs in source-repositories files and other
places, by ignoring curl's inability to determine an HTTP status code
for them.

Change-Id: Ie226ce05ecb912b23cedc73fd7ba53c0b9c0fe35

elements/cache-url/bin/cache-url

@@ -35,7 +35,7 @@ else
 fi
 
 rcode=$(curl -L -o $tmp -w '%{http_code}' $url $time_cond)
-if [ "$rcode" = "200" ] ; then
+if [ "$rcode" == "200" -o "${url:0:7}" == "file://" ] ; then
     # In cases where servers ignore the Modified time,
     # curl cancels the download, outputs a 200 and leaves
     # the output file untouched, we don't want this empty file.