Search project in domain when it's defined

Since there might be several projects with the same name in different
domains, it's required to define domain_id during project search.
Otherwise openstacksdk will raise "Multiple matches found" error

(cherry picked from commit 33ab7ca162)

changelogs/fragments/60410-search-project-in-domain.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - os_user - when domain is provided, default_project will be taken from this domain.

lib/ansible/modules/cloud/openstack/os_user.py

@@ -172,8 +172,8 @@ def _get_domain_id(cloud, domain):
     return domain_id
 
 
-def _get_default_project_id(cloud, default_project, module):
-    project = cloud.get_project(default_project)
+def _get_default_project_id(cloud, default_project, domain_id, module):
+    project = cloud.get_project(default_project, domain_id=domain_id)
     if not project:
         module.fail_json(msg='Default project %s is not valid' % default_project)
 
@@ -224,7 +224,7 @@ def main():
                     module.fail_json(msg=msg)
             default_project_id = None
             if default_project:
-                default_project_id = _get_default_project_id(cloud, default_project, module)
+                default_project_id = _get_default_project_id(cloud, default_project, domain_id, module)
 
             if user is None:
                 if description is not None: