fix OraNumber object creation for older ruby-oci8 versions
fix OraNumber object creation for older ruby-oci8 versions

rsim/ruby-plsql,jgebal/ruby-plsql,yahonda/ruby-plsql,JDominator/ruby-plsql,flash-gordon/ruby-plsql,rsim/ruby-plsql,jgebal/ruby-plsql,JDominator/ruby-plsql,jgebal/ruby-plsql,yahonda/ruby-plsql