Handle failed http requests better

[wfaulk]

Any failed http request results in the program exiting:

lastpass-cli/http.c

Lines 344 to 345 in 8767b5e

	if (ret != CURLE_OK && ret != CURLE_ABORTED_BY_CALLBACK)
	die("%s.", curl_easy_strerror(ret));

If it's just getting the blob, it could still function with the local cache. It should either continue with the local cache, probably with a warning, or at least indicate that the local cache can be specified with --sync=no.

[wfaulk]

There seemed to have been a temporary outage of the lastpass.com web site that caused the CLI to produce the error:

Error: HTTP response code said error.

and exit without using the cached blob until I found the --sync=no option.

[artm]

Had encountered the same problem today, except lpass is integrated across multiple scripts and CLI tools in my workflow. My workaround is to set longer autosync time with export LPASS_AUTO_SYNC_TIME=$(( 24 * 60 * 60 )) in the shell where I run my tools from. As long as only read access to preexisting secrets is needed this fixes the infantile error message ("Computer said no" or something to that extent).