Change "if instantaneous" statemt with more appropriate conditional

Matches commit eeedbc6 in ESCOMP#2838

src/main/histFileMod.F90

@@ -3409,7 +3409,7 @@ subroutine htape_timeconst(t, f, mode)
 
        dim1id(1) = time_dimid
        str = 'days since ' // basedate // " " // basesec
-       if (tape(t)%hlist(1)%avgflag /= 'I') then  ! NOT instantaneous fields tape
+       if (hist_avgflag_pertape(t) /= 'I') then  ! NOT instantaneous fields tape
           step_or_bounds = 'time_bounds'
           long_name = 'time at exact middle of ' // step_or_bounds
           call ncd_defvar(nfid(t,f), 'time', tape(t)%ncprec, 1, dim1id, varid, &
@@ -3472,7 +3472,7 @@ subroutine htape_timeconst(t, f, mode)
           long_name = 'time step')
 
        dim2id(1) = hist_interval_dimid;  dim2id(2) = time_dimid
-       if (tape(t)%hlist(1)%avgflag /= 'I') then  ! NOT instantaneous fields tape
+       if (hist_avgflag_pertape(t) /= 'I') then  ! NOT instantaneous fields tape
           call ncd_defvar(nfid(t,f), 'time_bounds', ncd_double, 2, dim2id, varid, &
              long_name = 'history time interval endpoints')
        end if
@@ -3505,7 +3505,7 @@ subroutine htape_timeconst(t, f, mode)
 
        timedata(1) = tape(t)%begtime  ! beginning time
        timedata(2) = mdcur + mscur/secspday  ! end time
-       if (tape(t)%hlist(1)%avgflag /= 'I') then  ! NOT instantaneous fields tape
+       if (hist_avgflag_pertape(t) /= 'I') then  ! NOT instantaneous fields tape
           time = (timedata(1) + timedata(2)) * 0.5_r8
           call ncd_io('time_bounds', timedata, 'write', nfid(t,f), nt=tape(t)%ntimes(f))
        else