Fix output state following an error state trapped by stpctl.F90

[acc]

The recent rearrangement of step has placed the main call to dia_wri at the top to the time step loop. If error conditions (large U, negative salinity etc.) are detected in stp_ctl (called at the
bottom of the loop), then dia_wri is again called in an attempt to
flush and close the mean files. This now raises a fatal error in
histcom.f90:

FATAL ERROR FROM ROUTINE histwrite

--> This variable as already been analysed at the present
--> time step

and the code aborts before creating the expected output.abort files.

A solution is to split the dual-purpose test at the bottom of dia_wri:

! 3. Close all files
! ---------------------------------------
IF( kt == nitend .OR. kindic < 0 ) THEN

CALL histclo( nid_T )
CALL histclo( nid_U )
CALL histclo( nid_V )
CALL histclo( nid_W )

ENDIF

making this test simply:

! 3. Close all files
! ---------------------------------------
IF( kt == nitend ) THEN

CALL histclo( nid_T )
CALL histclo( nid_U )
CALL histclo( nid_V )
CALL histclo( nid_W )

ENDIF

and placing the following before the IF(kt == nit000 ) test at the
top of dia_wri:

! Close all files and return if an error has been detected
! --------------------------------------------------------
IF( kindic < 0 ) THEN

CALL histclo( nid_T )
CALL histclo( nid_U )
CALL histclo( nid_V )
CALL histclo( nid_W )
RETURN

ENDIF