Description of problem: strace in Fedora 9 allowed both i386 and x86_64 strace to be installed. Upgrading from Fedora 9 to rawhide fails because of a file conflict between old strace.i386 and new strace.x86_64. Removing strace.i386 lets the upgrade continue.
If there is a problem here at all, it is not an strace issue, just a distro issue. If you simultaneously upgrade to the same strace-V-R for both i386 and x86_64, then there is no problem. If you had both arch rpms installed under F-9, I don't think that was done by normal distro means, since the x86_64 install image and repos do not contain strace.i386 rpms. The report failed to show the actual conflict, which was a bad omission. I tried it myself using rpm by hand (since there is no canonical distro way to make this happen AFAICT), and got the conflict on the man page file. That differs because it changed between upstream strace versions, as you might expect.
strace only existed for the base arch in Fedora 9 (AFAICT). The same is true in F10. Closing; I'm curious how you got both arches installed under F9.