seqRecord: fix upper display limit of the DLYn fields

get_graphic_double() assigns lower_disp_limit twice and never writes
upper_disp_limit, so a DBR_GR_DOUBLE read of any DLYn field reports
the inverted range lower=10, upper=0.  The second assignment was
evidently meant for the upper limit; the 0 in the upper slot is the
zeroed buffer dbAccess.c hands to the RSET, not a chosen value.

Both assignments date from commit 27e80be2e5 which introduced the
DLYn limits, so every release since 3.14.11 reports the inverted
range over both CA (DBR_GR/CTRL) and PVA (display.limitLow/High).

Extend seqTest with a DBR_GR_DOUBLE read of DLY0; the new cases
fail with lower=10, upper=0 before this fix.

modules/database/src/std/rec/seqRecord.c

@@ -327,7 +327,7 @@ static long get_graphic_double(DBADDR *paddr, struct dbr_grDouble *pgd)
         switch (fieldOffset & 3) {
         case 0: /* DLYn */
             pgd->lower_disp_limit = 0.0;
-            pgd->lower_disp_limit = 10.0;
+            pgd->upper_disp_limit = 10.0;
             return 0;
         case 2: /* DOn */
             dbGetGraphicLimits(get_dol(prec, fieldOffset),