clean.adb (Delete): Do not output warnings when in quiet output and not in verbose...

clean.adb (Delete): Do not output warnings when in quiet output and not in verbose mode.

2004-10-26  Vincent Celier  <celier@gnat.com>

	* clean.adb (Delete): Do not output warnings when in quiet output and
	not in verbose mode.
	(Force_Deletions): New Boolean flag, defaulted to False
	(Delete): Only delete a file if it is writable, and when
	Force_Deletions is True.
	(Parse_Cmd_Line): New switch -f: set Force_Deletions to True
	(Usage): Line for new switch -f
	(Clean_Directory): Use GNAT.OS_Lib.Set_Writable instead of rolling our
	own.

From-SVN: r89646