[Axis2] Prefix for errors

[Samisa Abeysinghe]

Hi All,
   We use "AXIS2_ERROR_" as the prefix for all error numbers. I see the 
following set of errors in the error.h file which violate this 
convention. I will add the prefix for consistancy.

       INVALID_MODULE_REF,
      
       PHASE_IS_NOT_SPECIFED,
      
       SERVICE_MODULE_CAN_NOT_REFER_GLOBAL_PHASE,
      
       INVALID_PHASE,

Thanks,
Samisa...