Extend fast-reboot STATE_DB entry timer (sonic-net#2577)

*Due to an issue of fallback from to cold-boot when using upgrade with fast-reboot combined with FW upgrade a short term solution is to extend the timer. Long term solution of using fast-reboot finalizer replacing the timer is in work.

Author: arfeigin

scripts/fast-reboot

@@ -532,7 +532,7 @@ case "$REBOOT_TYPE" in
         check_warm_restart_in_progress
         BOOT_TYPE_ARG=$REBOOT_TYPE
         trap clear_boot EXIT HUP INT QUIT TERM KILL ABRT ALRM
-        sonic-db-cli STATE_DB SET "FAST_REBOOT|system" "1" "EX" "180" &>/dev/null
+        sonic-db-cli STATE_DB SET "FAST_REBOOT|system" "1" "EX" "210" &>/dev/null
         config warm_restart enable system
         ;;
     "warm-reboot")