init: check permissions on rc.d files

We try to unconditionally execute /etc/rc.d/* files, even if they're
not executable - an easy way of temproarily disabling a service. When
this happens, we get a permission denied error on boot.

This change only tries to run execulable startup scripts.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@9607 3c298f89-4303-0410-b956-a3cf2f4a3e73