[rpmbuild] correct the nosync.i686 requirement
Per dnf report:
Problem: cannot install the best candidate for the job
- nothing provides nosync.i686 needed by copr-builder-0.26.git.1.c5bb33f4-1.fc31.x86_64
The 'nosync.i686' is actually yum/dnf construct, not a real
provide to depend on.