Fix tests to use path_to_backup instead src_file

Src_file option was changed to path_to_backup in freezer git repository
below, but tests were never changed, this patch is fixing this behaviour.

Freezer's change :
c7f71ff70b

Doc changes in freezer:
https://review.opendev.org/#/c/705003/

Changes in freezer-api:
https://review.opendev.org/#/c/705012/

Change-Id: I64a3e36ac68de5c45a93b56be83b017ce9f1221c

freezer_tempest_plugin/tests/freezer_api/api/test_api_actions.py

@@ -74,7 +74,7 @@ class TestFreezerApiActions(base.BaseFreezerApiTest):
                 {
                     'action': 'backup',
                     'mode': 'fs',
-                    'src_file': '/dev/null',
+                    'path_to_backup': '/dev/null',
                     'backup_name': 'test freezer api actions',
                     'container': 'test_freezer_api_actions_container',
                     'max_backup_level': 1,
@@ -129,9 +129,9 @@ class TestFreezerApiActions(base.BaseFreezerApiTest):
         action = freezer_action_json['action']
         self.assertEqual('backup', action)
 
-        self.assertIn('src_file', freezer_action_json)
-        src_file = freezer_action_json['src_file']
-        self.assertEqual('/dev/null', src_file)
+        self.assertIn('path_to_backup', freezer_action_json)
+        path_to_backup = freezer_action_json['path_to_backup']
+        self.assertEqual('/dev/null', path_to_backup)
 
         self.assertIn('always_backup_level', freezer_action_json)
         always_backup_level = freezer_action_json['always_backup_level']

freezer_tempest_plugin/tests/freezer_api/api/test_api_jobs.py

@@ -27,7 +27,7 @@ fake_job = {
                     {
                         "action": "backup",
                         "mode": "fs",
-                        "src_file": "/home/tylerdurden/project_mayhem",
+                        "path_to_backup": "/home/tylerdurden/project_mayhem",
                         "backup_name": "project_mayhem_backup",
                         "container": "my_backup_container",
                     },

freezer_tempest_plugin/tests/freezerclient/test_freezer_cmd_action.py

@@ -28,7 +28,7 @@ class TestFreezerCmdAction(base.BaseFreezerTest):
              {\
                "action": "backup",\
                "mode": "fs",\
-               "src_file": "/tmp/source",\
+               "path_to_backup": "/tmp/source",\
                "backup_name": "my-first-backup",\
                "container": "/tmp/backup/",\
                "storage": "local"\