A short while ago support for RAID arrays was added to rc.sysinit:

if [ -f /etc/mdadm.conf -a "`grep ^ARRAY /etc/mdadm.conf 2>/dev/null`" ]; then
[...]
fi

But the first test is completely pointless since the shell test AND ("[ ... -a ... ]") is not an conditional AND like in C/C++. The grep is excuted anyway regardless of the result of the first test. The redirection of all messages to /dev/null is an ugly way to hide this missbehaviour. A simple correction is:

if [ -f /etc/mdadm.conf ] && grep -q ^ARRAY /etc/mdadm.conf; then
[...]
fi

Or if performance does not matter:

if grep -q -s ^ARRAY /etc/mdadm.conf; then
[...]
fi