Deprecate CONF.monkey_patch

This option, along with monkey_patch_modules, is
arguably worse than hooks since it doesn't even
rely on having in-tree code. It's super legacy,
not tested, not supported and is a barrier to
interoperability, so we should deprecate it for
removal.

This also allows us to deprecate the default_publisher_id
option which is used for the legacy notify_decorator
which is only used if specified with the monkey_patch_modules
option, which is also deprecated here.

Also removed the nova.api.ec2.cloud mention from the
config option help text for monkey_patch_modules
since that isn't valid in nova anymore.

Change-Id: Id793ac2c5cdc5dc473f95eac53b77617a1e389da

nova/utils.py

@@ -498,8 +498,9 @@ def format_remote_path(host, path):
     return "%s:%s" % (safe_ip_format(host), path)
 
 
+# TODO(mriedem): Remove this in Rocky.
 def monkey_patch():
-    """If the CONF.monkey_patch set as True,
+    """DEPRECATED: If the CONF.monkey_patch set as True,
     this function patches a decorator
     for all functions in specified modules.
     You can set decorators for each modules
@@ -517,6 +518,7 @@ def monkey_patch():
     # If CONF.monkey_patch is not True, this function do nothing.
     if not CONF.monkey_patch:
         return
+    LOG.warning('Monkey patching nova is deprecated for removal.')
     if six.PY2:
         is_method = inspect.ismethod
     else: