schema_args: Do not generate option for read-only properties

The schema_args decorator generates command line options based on the
properties defined in a schema. This commit makes sure read-only
properties are skipped during this process, since trying to modify their
value would result in a Glance error.

Closes-Bug: #1561828
Change-Id: I7ccc628a23c9ebdaeedcb9e6d43559f497ce9555

glanceclient/common/utils.py

@@ -123,6 +123,8 @@ def schema_args(schema_getter, omit=None):
             for name, property in properties.items():
                 if name in omit:
                     continue
+                if property.get('readOnly', False):
+                    continue
                 param = '--' + name.replace('_', '-')
                 kwargs = {}