Throw a more user-friendly exception on "No address associated with hostname" error

[Kami]

Usually this issue represents a bug in the driver (host connection class attribute being set to an incorrect value), but the original exception is kinda cryptic so it's hard for the users to figure out what is going on.

Before:

Traceback (most recent call last):
  File "example.py", line 5, in <module>
    print driver.list_zones()
  File "/home/kami/w/lc/libcloud/libcloud/dns/drivers/godaddy.py", line 146, in list_zones
    '/v1/domains/').object
  File "/home/kami/w/lc/libcloud/libcloud/common/base.py", line 827, in request
    headers=headers)
  File "/usr/lib64/python2.7/httplib.py", line 1053, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib64/python2.7/httplib.py", line 1093, in _send_request
    self.endheaders(body)
  File "/usr/lib64/python2.7/httplib.py", line 1049, in endheaders
    self._send_output(message_body)
  File "/usr/lib64/python2.7/httplib.py", line 893, in _send_output
    self.send(msg)
  File "/usr/lib64/python2.7/httplib.py", line 855, in send
    self.connect()
  File "/home/kami/w/lc/libcloud/libcloud/httplib_ssl.py", line 284, in connect
    self.timeout)
  File "/usr/lib64/python2.7/socket.py", line 557, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
socket.gaierror: [Errno -5] No address associated with hostname

After:

Traceback (most recent call last):
  File "example.py", line 5, in <module>
    print driver.list_zones()
  File "/home/kami/w/lc/libcloud/libcloud/dns/drivers/godaddy.py", line 146, in list_zones
    '/v1/domains/').object
  File "/home/kami/w/lc/libcloud/libcloud/common/base.py", line 842, in request
    raise socket.gaierror(msg)
socket.gaierror: [Errno -5] No address associated with hostname. Perhaphs "host" Connection class attribute (GoDaddyDNSConnection.connection) is set to an invalid, non-hostname value (http://www.google.com)?

[tonybaloney]

It's too late now, but you meant 'perhaps'?

[Kami]

Perhaps :P

Joking aside, good catch, will push a fix.