Fixed bug in AlarmIncrementMonths: increment month at end of loop

Fixed an issue in routine AlarmIncrementMonths (in module
History/histcontainer_mod.F90).  We have to increment the month at the
end of the DO loop after updating the nDays variable.  Otherwise this
causes an incorrect count of days.

Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>

History/histcontainer_mod.F90

@@ -1636,15 +1636,6 @@ SUBROUTINE AlarmIncrementMonths( IntervalYmd, Year, Month, Increment )
     ! Loop over the requested # of months
     DO T = 0, nMonths-1
 
-       ! Increment the month
-       MM = MM + 1
-
-       ! Increment the year if we straddle New Year's Day
-       IF ( MM > 12 ) THEN
-          MM   = 1
-          YYYY = YYYY + 1
-       ENDIF
-
        ! Keep a running total of the number of days in the interval
        nDays = nDays + DpM(MM)
 
@@ -1653,6 +1644,15 @@ SUBROUTINE AlarmIncrementMonths( IntervalYmd, Year, Month, Increment )
           nDays = nDays + 1
        ENDIF
 
+       ! Increment the month for next iteration
+       MM = MM + 1
+
+       ! Also increment the year if we straddle New Year's Day
+       IF ( MM > 12 ) THEN
+          MM   = 1
+          YYYY = YYYY + 1
+       ENDIF
+
     ENDDO
 
     ! Convert from days to seconds