Fix 'redeclaration of COBranchRevisionReadingOptions with different type' build error on OS X 10.9

git-svn-id: svn://svn.gna.org/svn/etoile/trunk/Etoile/Frameworks/CoreObject@9916 7b3f36aa-e6db-49c1-8b4c-66eac1997e64