sato-icon-theme: add more compatibility symlinks

sato-icon-theme: add more compatibility symlinks

libfm uses "preferences-desktop", so link it to the close-enough
"preferences-sytem".

x11vnc uses "computer", link it to "terminal".

pcmanfm uses "system-file-manager", link it to "file-manager".

[ YOCTO #4062 ]

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>