server: we can lost bufr importing from AMQP

This commit:
https://github.com/r-map/rmap/commit/040f21d0ea77420190c168877285dcd6e3870684
catch error when importing wrong bufr from AMQP but we can lost some messages (bufr after the wrong).

Related to https://github.com/ARPA-SIMC/dballe/issues/288