mv /boot/initramfs-2.6.32-358.0.1.el6.i386.img /boot/initramfs-2.6.32-358.0.1.el6.i386-nouveau.img dracut /boot/initramfs-2.6.32-358.0.1.el6.i386.img 2.6.32-358.0.1.el6.i386
Interestingly enough, the new initramfs that I got from this command is slightly smaller than the one that I already had in /boot.
Sadly, this made no difference. When I booted the machine, I still got the same dracut warning and kernel panic.
To me looks like the initramfs does not contain all the needed "pieces" to boot the machine.
Try investigating the dracut options to include more modules or filesystem etc. starting with --lvmconf and --mdadmconf