I removed a hard drive containing a swap volume and my system does not boot
anymore. It waits indefinitely for the missing swap device.

The behaviour (no timeout) was questioned by Thomas:

http://thread.gmane.org/gmane.linux.kernel.initramfs/3786

First, I tried omit 'resume' module without sucess. It took some time to find
an apparently SUSEism nowaitforswap="yes" that fixed it.

I see this patch on Factory. But it does not appear to be applied on 13.2:

https://build.opensuse.org/package/view_file/openSUSE:Factory/dracut/0046-dracut-Do-not-wait-for-swap-device.patch?expand=1

So, for now, I think nowaitforswap="yes" must be assumed when we omit the
'resume' module at least (my server does not hibernate...).

dracut-037-17.6.1.x86_64