Avoid webservice methods being denied fieldvalues they need by retrieve_entity_info

[Luke1982]

https://github.com/tsolucio/corebos/blob/d726b5dcd65db2b27b9f8c2b17dafc87dd887cfa/data/CRMEntity.php#L1045

The line above demonstrates we solved this for the 'update field' task in workflows. When some background process (e.g. webservice calls in this matter) retrieves an entity they need to update or revise, they need crucial info like the modifiedtime for example. Right now retrieve_entity_info doesn't return those when the user in question does not have access. We should write an exception for these processes since they can lead to errors that are very hard to trace back to missing permissions (like database errors).