Fix FM error messages for forbidden requests

The CLI error messages for users with reader role were not clear to the
operator and this change fixes this.

Test Plan:

PASS: In an AIO-SX with this change present, create a new openstack user
with reader role and through this user execute the commands:
fm alarm-list
fm alarm-delete <uuid>
fm event-suppress --alarm_id <alarm_id>
and check that the "alarm-list" command is executed without errors and
that the error message of the other commands changes from:
"HTTP Client Error (HTTP 403) (Request-ID: req-<req_id>)"
to:
"Error: Forbidden."

Story: 2010149
Task: 46620

Signed-off-by: Joao Victor Portal <Joao.VictorPortal@windriver.com>
Change-Id: I45007a7f5319ef0a0238a07d671a859b5081660a

python-fmclient/fmclient/fmclient/common/exceptions.py

@@ -85,6 +85,15 @@ class HTTPClientError(HttpError):
     message = _("HTTP Client Error")
 
 
+class HTTPForbidden(HTTPClientError):
+    """HTTP 403 - Forbidden
+
+    Exception for cases in which the server understands the request
+    but refuses to authorize it.
+    """
+    message = _("HTTP Client Error: Forbidden")
+
+
 class HTTPNotFound(HTTPClientError):
     """HTTP 404 - Not Found
 
@@ -172,6 +181,8 @@ def from_response(response, method, url=None):
     except KeyError:
         if 500 <= response.status_code < 600:
             cls = HttpServerError
+        elif 403 == response.status_code:
+            cls = HTTPForbidden
         elif 404 == response.status_code:
             cls = HTTPNotFound
         elif 400 <= response.status_code < 500:

python-fmclient/fmclient/fmclient/shell.py

@@ -17,6 +17,7 @@ import sys
 from oslo_utils import importutils
 
 import fmclient
+from fmclient.common import exceptions
 from fmclient.common import utils
 from fmclient import exc
 from fmclient import client
@@ -292,6 +293,8 @@ class FmShell(object):
             args.func(client, args)
         except exc.Unauthorized:
             raise exc.CommandError("Invalid Identity credentials.")
+        except exceptions.HTTPForbidden:
+            raise exc.CommandError("Error: Forbidden.")
 
     def do_bash_completion(self, args):
         """Prints all of the commands and options to stdout.