GUI: Updated CLI Get BMC DateTime and Modify BMC Date keywords

Changes:
    - Modified keyword called as CLI Get BMC DateTime.
    - Modified keyword called as Modify BMC Date .

Tested:
    - Successfully ran
      redfish/managers/test_certificate.robot

Change-Id: I1341b3670bd5ae6d496d06ea0e32e43091e7c62e
Signed-off-by: rramyasr-in <rramyasr@in.ibm.com>
diff --git a/lib/utils.robot b/lib/utils.robot
index 084d400..1411e23 100755
--- a/lib/utils.robot
+++ b/lib/utils.robot
@@ -790,7 +790,7 @@
 CLI Get BMC DateTime
     [Documentation]  Returns BMC date time from date command.
 
-    ${bmc_time_via_date}  ${stderr}  ${rc}=  BMC Execute Command  date +"%Y-%m-%d %H:%M:%S"  print_err=1
+    ${bmc_time_via_date}  ${stderr}  ${rc}=  BMC Execute Command  date +"%Y-%m-%dT%H:%M:%S"  print_err=1
     RETURN  ${bmc_time_via_date}