Description of problem:

I got an error involving qemu-block-rbd while running dnf system-upgrade to F30.

Problem 3: package qemu-block-rbd-2:3.0.0-3.fc29.i686 requires libcapstone.so.3, but none of the providers can be installed
  - capstone-3.0.5-2.fc29.i686 does not belong to a distupgrade repository
  - problem with installed package qemu-block-rbd-2:3.0.0-3.fc29.i686

I have many of the qemu i686 packages installed. 

sudo dnf system-upgrade download --refresh --releasever=30 --skip-broken --allowerasing showed qemu-block-rbd being removed:

Removing dependent packages:
...
qemu-block-rbd      i686   2:3.0.0-3.fc29           @updates-testing  31 k


Version-Release number of selected component (if applicable):
qemu-block-rbd-2:3.0.0-3.fc29.i686
qemu-3.1.0-4.fc30.3
capstone-3.0.5-2.fc29.i686
capstone-4.0.1-3.fc30

How reproducible:
5 of 5 times

Steps to Reproduce:
In F29 with updates-testing enabled and qemu-block-rbd-2:3.0.0-3.fc29.i686 installed
1. sudo dnf upgrade --refresh
2. sudo dnf system-upgrade download --refresh --releasever=30
3. sudo dnf system-upgrade download --refresh --releasever=30 --skip-broken --allowerasing

Actual results:
dnf system-upgrade error involving qemu-block-rbd

Expected results:
no error

Additional info:

qemu-3.1.0-4.fc30.3's changelog on koji noted the following. 
* Mon Dec 10 2018 Daniel P. Berrangé <berrange> - 2:3.1.0-0.2.rc1 - Disable RBD on 32-bit arches
https://koji.fedoraproject.org/koji/buildinfo?buildID=1219349

Obsoleting qemu-block-rbd on 32-bit architectures might prevent this error if it isn't going to be built again for them. capstone-4.0.1-3.fc30 provides libcapstone.so.4, but keeping qemu-block-rbd-2:3.0.0-3.fc29 might conflict since it requires libcapstone.so.3.