CI: Do not set scheduler in qemu-1-setup.sh

[tonyhutter]

Motivation and Context

Fix qemu-1-setup CI failures

Description

We've seen some qemu-1-setup failures while trying to change the runner's block device scheduler value to 'none':

We have a single 150GB block device
Setting up swapspace version 1, size = 16 GiB (17179865088 bytes)
no label, UUID=7a790bfe-79e5-4e38-b208-9c63fe523294
tee: '/sys/block/s*/queue/scheduler': No such file or directory

Luckily, we don't need to set the scheduler anymore on modern kernels: #9778 (comment)

This commit just removes the code that sets the scheduler.

How Has This Been Tested?

qemu-1-setup passed on local CI

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Quality assurance (non-breaking change which makes the code more robust against bugs)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.