Fix file extension parsing

Author: glebm

fileLister.h

@@ -12,7 +12,7 @@ struct T_FILE
     T_FILE(std::string p_name, bool is_symlink, unsigned long int p_size = 0)
         : m_name(std::move(p_name)),
           is_symlink(is_symlink),
-          m_ext(File_utils::getLowercaseFileExtension(p_name)),
+          m_ext(File_utils::getLowercaseFileExtension(m_name)),
           m_size(p_size) {}
     T_FILE(const T_FILE &p_source) = default;
     T_FILE &operator=(const T_FILE &p_source) = default;