[fast-reboot] revert the change of disabling counter polling before fast-reboot (#1744)

What I did
The change being removed was introduced with PR#1174 with the condition that flex counter polling will be enabled in the boot up path unconditionally. However, a change was made to enable_counters.py to only enable counters when the configuration is missing (sonic-buildimage PR#7735). After the later change, the disabled flex counters will not be enabled when fast-reboot into the same image.

How to verify it
run fast-reboot test and snmp test, without the fix, the snmp test would fail. With the fix, the snmp test passes.

Signed-off-by: Ying Xie [email protected]

Author: yxieca

scripts/fast-reboot

@@ -36,7 +36,6 @@ EXIT_ORCHAGENT_SHUTDOWN=10
 EXIT_SYNCD_SHUTDOWN=11
 EXIT_FAST_REBOOT_DUMP_FAILURE=12
 EXIT_FILTER_FDB_ENTRIES_FAILURE=13
-EXIT_COUNTERPOLL_DISABLE_FAILURE=14
 EXIT_NO_CONTROL_PLANE_ASSISTANT=20
 EXIT_SONIC_INSTALLER_VERIFY_REBOOT=21
 
@@ -671,19 +670,6 @@ then
   systemctl stop "$service_name"
 fi
 
-if [[ "$REBOOT_TYPE" = "fast-reboot" ]]; then
-    CONFIG_DB_FILE=/etc/sonic/config_db.json
-    COUNTERPOLL_DISABLE_RC=0
-    # Disable counters in config_db.json
-    /usr/local/bin/counterpoll config-db disable $CONFIG_DB_FILE || COUNTERPOLL_DISABLE_RC=$?
-    if [[ COUNTERPOLL_DISABLE_RC -ne 0 ]]; then
-        error "Failed to disable counterpoll. Exit code: $COUNTERPOLL_DISABLE_RC"
-        /usr/local/bin/counterpoll config-db enable $CONFIG_DB_FILE || COUNTERPOLL_DISABLE_RC=$?
-        unload_kernel
-        exit "${EXIT_COUNTERPOLL_DISABLE_FAILURE}"
-    fi
-fi
-
 # Update the reboot cause file to reflect that user issued this script
 # Upon next boot, the contents of this file will be used to determine the
 # cause of the previous reboot