Avoid HTTP requests on previously error'd URIs.

Avoid HTTP requests on previously error'd URIs.

+Create type to set RRDP URIs request status (error, unvisited, visited). The status is set accordingly to the result of the last request and processing of the RRDP Update Notification URIs; during RRDP loading, the status is validated to either do a request (URIs hasn't been visited) or skip it (was previously visited or had an error). If a request had an error, then continue the access methods flow considering priorities.
+Update RET_NOT_FOUND_URI macro, it always returned the same error code.
+Remove downloaded files via HTTP (and its local directory structure) whenever there's an error during the download process.