This patch adds a method `execWithElevatedPrivilege()` which can be used by other methods of `FileProtocol` class when there occurs an error due to insufficient privileges.
It takes the following arguments,
1. `int error` : to check if error == `EACCES`. otherwise don't continue.
2. `ActionType` : the c-library function to execute
3. three QVariants: the arguments to the function
This method makes use of the signal `execPrivilegeData` to check if the job requires privileges to be elevated and to ask the job to show a warning/confirmation dialog.