Regression fix:  make mod_dav_svn notice svn:mime-type again on public URIs.
Regression fix:  make mod_dav_svn notice svn:mime-type again on public URIs.

* repos.c (dav_svn_set_headers):  followup to r7797 -- don't be too
  overzealous.  'regular' resources can have mime-types too, not just
  'version' ones.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion