[JIRA SONIC-62439] Display message "Not available" when no

configuration has been updated.

sonic# show system config-update-time
Not available
sonic#
sonic# configure terminal
sonic(config)# interface Vlan 10
sonic(conf-if-Vlan10)# do show system config-update-time
Mon 25 Feb 2019 04:41:31 AM UTC
sonic(conf-if-Vlan10)#

Change-Id: I58c1d5a05d556a66d83a37f762c95764730aa4ad

Author: maheshwari-mayank

CLI/actioner/sonic-cli-sys.py

@@ -126,17 +126,19 @@ def run(func, args):
                     return
                 show_cli_output(args[0], value["cpu"])
             elif "openconfig-system:config-time" in list(response.keys()):
+                newResp = {}
                 value = response["openconfig-system:config-time"]
-                if value is None:
+                if value is None or value == "0":
+                    newResp["openconfig-system:config-time"] = "Not available"
+                    show_cli_output(args[0], newResp)
                     return
                 # Convert to seconds
-                dt = datetime.fromtimestamp(int(value) / 1000000000)
+                dt = datetime.fromtimestamp(int(value) / 1000000000.0)
                 dispTime = dt.strftime("%a %d %b %Y %I:%M:%S %p")
                 # reset timezone in this session before read it
                 time.tzset()
                 tz = time.strftime("%Z")
                 dispTime = dispTime + " " + tz
-                newResp = {}
                 newResp["openconfig-system:config-time"] = dispTime
                 show_cli_output(args[0], newResp)
             elif "openconfig-system:processes" in list(response.keys()):