php-driver: add correct namespace for php driver in exceptions.thrift
php-driver: add correct namespace for php driver in exceptions.thrift

JerJohn15/concourse,hcuffy/concourse,kylycht/concourse,cinchapi/concourse,cinchapi/concourse,remiemalik/concourse,kylycht/concourse,dubex/concourse,dubex/concourse,vrnithinkumar/concourse,dubex/concourse,kylycht/concourse,vrnithinkumar/concourse,remiemalik/concourse,hcuffy/concourse,JerJohn15/concourse,JerJohn15/concourse,dubex/concourse,hcuffy/concourse,vrnithinkumar/concourse,cinchapi/concourse,dubex/concourse,cinchapi/concourse,JerJohn15/concourse,remiemalik/concourse,remiemalik/concourse,dubex/concourse,kylycht/concourse,cinchapi/concourse,JerJohn15/concourse,JerJohn15/concourse,cinchapi/concourse,vrnithinkumar/concourse,kylycht/concourse,vrnithinkumar/concourse,hcuffy/concourse,kylycht/concourse,remiemalik/concourse,hcuffy/concourse,hcuffy/concourse,vrnithinkumar/concourse,remiemalik/concourse