(svn_fs__dag_is_mutable):  implement.
(svn_fs__dag_is_mutable):  implement.

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