rest-api: Swagger scripts were not replacing format variable in file brief

Given resource paths did not have 'json' substituted in for the '{format}'. For
some auto generated documentation/comment strings it resulted in something like
the following:

"... REST handler for /api-docs/sounds.{format}"

This patch makes sure the resource api's path is properly substituted.

ASTERISK-25472 #close

Change-Id: Ie3e950a35db4043e284019d6c9061f3b03922e23

rest-api-templates/swagger_model.py

@@ -691,7 +691,7 @@ class ResourceApi(Stringify):
     def load(self, api_json, processor, context):
         context = context.next_stack(api_json, 'path')
         validate_required_fields(api_json, self.required_fields, context)
-        self.path = api_json['path']
+        self.path = api_json['path'].replace('{format}', 'json')
         self.description = api_json['description']
 
         if not self.path or self.path[0] != '/':
@@ -700,7 +700,7 @@ class ResourceApi(Stringify):
         return self
 
     def load_api_declaration(self, base_dir, processor):
-        self.file = (base_dir + self.path).replace('{format}', 'json')
+        self.file = (base_dir + self.path)
         self.api_declaration = ApiDeclaration().load_file(self.file, processor)
         processor.process_resource_api(self, [self.file])