Poor error handling if hitting the max number of requests

[jolexa]

Hello, thanks for opensourcing this little project. I'm reporting a minor issue, not a big deal so I'm not expecting it to get fixed since the resolution is to just try later.

Rate limiting
The CloudFlare API sets a maximum of 1,200 requests in a five minute period
https://api.cloudflare.com/#requests

If you exceed this rate limit while using whitelist.py then you will get a successful log message without successfully hitting the CF API.

<snip>
2016-01-01 20:48:25,782 [ERROR]: Error deleting access rule 565c6267c40dbd004bae4ef063c64136 (IP: 197.231.221.211)
Traceback (most recent call last):
  File "./whitelist.py", line 265, in main
    remove_access_rule(session, rule_id, zone_id)
  File "./whitelist.py", line 116, in remove_access_rule
    r.raise_for_status()
  File "/usr/lib64/python2.7/site-packages/requests/models.py", line 840, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
HTTPError: 429 Client Error: Too Many Requests for url: https://api.cloudflare.com/client/v4/user/firewall/access_rules/rules/565c6267c40dbd004bae4ef063c64136
2016-01-01 20:48:25,783 [INFO]: Removed 799 matching Tor access rules.

The last line is what I am talking about. This is probably only an issue with accounts that have multiple domains, etc. Using default value, the problem will not present itself.