Handle 401 Errors

[sphen13]

If you have the wrong key info we get a 401 on authorization. Right now this fails spectacularly - we need to handle it gracefully.

File "/usr/local/munki/middleware_b2.py", line 62, in authorize_b2 response = urllib2.urlopen(request) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 154, in urlopen return opener.open(url, data, timeout) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 437, in open response = meth(req, response) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 550, in http_response 'http', request, response, code, msg, hdrs) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 475, in error return self._call_chain(*args) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 409, in _call_chain result = func(*args) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 558, in http_error_default raise HTTPError(req.get_full_url(), code, msg, hdrs, fp) urllib2.HTTPError: HTTP Error 401: