Change 'status_code' to 'http_status' to parse SDK's exception

OpenstackSDK has changed the 'status_code' parameter to 'http_status'
in the recent commit Ib873c038358fb318ae46e8bc5bd3b4dfb683daaa.
Senlinclient should change it too to parse SDK's exception.

Change-Id: I5f8a0119c1f002a8c304f2f81a9f50dc7884e776

senlinclient/common/exc.py

@@ -239,7 +239,7 @@ def parse_exception(exc):
             # If the exc.details is not in JSON format
             record = {
                 'error': {
-                    'code': exc.status_code,
+                    'code': exc.http_status,
                     'message': exc.details,
                 }
             }