Fix the Windows buildbot, yet again.
Fix the Windows buildbot, yet again.

There's a bug in here somewhere, but I'm not sure if this commit is the
fix or just a plastering over the real issue.  However, this change does
get the build working again, and I'll keep investigating the root cause.

* subversion/libsvn_fs_fs/fs_fs.c
  (write_final_rev): If our rep doesn't have a sha1 hash, then don't
    attempt to write it to the rep cache.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@874472 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion