Quote URL in curl output to handle query params

Copy and pasting the generated curl output into a shell doesn't
work when the URL includes an ampersand, as the URL isn't quoted.

This simplifies the logic in client.http_log_req to be able to
output the URL and method separately and quote the URL.

Change-Id: I1e497886ea9334771ab91e657e7c1121d89f7f33
Merge "Quote URL in curl output to handle query params"