Adapt meaning of full_steps

[dcesari]

In subroutine recompute_stat_proc_agg_common around

libsim/vol7d/stat_proc_engine.F90

Line 431 in 1235235

IF (optio_log(full_steps)) THEN

the use of full_steps should be different if we are dealing with an analysis or forecast dataset, now it is always treated as in the case of an analysis dataset.

[dcesari]

Some work has been done in df3c61b, check if the full_step case has yet to be applied in forecast mode by aggregation.