Fix inconsistent --debug messages on image-update

image-update --debug message no longer adds '-d "None"' to the curl command that
is output. This keeps the curl output consistent with the client
request.

Fixes bug #1172702

Change-Id: I34ceeb6f4a67c753ca3a805ec11240a99ce38ec4

glanceclient/common/http.py

@@ -126,7 +126,7 @@ class HTTPClient(object):
         if self.connection_kwargs.get('insecure'):
             curl.append('-k')
 
-        if 'body' in kwargs:
+        if kwargs.get('body') is not None:
             curl.append('-d \'%s\'' % kwargs['body'])
 
         curl.append('%s%s' % (self.endpoint, url))