TYPO3 Core

When trying to delete a folder recursively in the backend filelist the following message appears:

Could not delete directory! Write-permission problem? Is directory "/path/to/fileadmin/testdata" empty? (You are not allowed to delete directories recursively).

The user actually IS allowed to delete recursively via (User Admin -> Mounts and Workspaces -> Directory: Delete recursively (rm -Rf)).

In TYPO3 4.2.1 this could be temporarely fixed by setting $GLOBALS['TYPO3_CONF_VARS']['BE']['disable_exec_function'] to '0', but this could cause other problems with safe_mode activated.

In the file t3lib/class.t3lib_extfilefunc.php Line 437 there is a completely unneccessary check for !$this->dont_use_exec_commands (which checks the status of $GLOBALS['TYPO3_CONF_VARS']['BE']['disable_exec_function']).
In previous versions of TYPO3 (< 4.2) a exec() call was used at this place but with TYPO3 4.2 this was eliminated.

The suggested solution is to eliminate the check for !$this->dont_use_exec_commands.

A patch for TYPO3 4.2.1 is attached.

Environment:
- Linux Debian 4.0
- PHP 5.2.0 CGI
- safe_mode: on

(issue imported from #M9307)