Quick certificate delete causes bmcweb to stop

bmcweb.service: Start request repeated too quickly
and hit start-limit-hit

Tested:
     robot -v OPENBMC_HOST:xx.xx.xx -v wait_time:200
           redfish/managers/test_certificate.robot

Change-Id: I29af1d7a9c92bfcc8b86ccc4a5b0a48d1c961dd6
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/certificate_utils.robot b/lib/certificate_utils.robot
index febe976..7f14bf3 100755
--- a/lib/certificate_utils.robot
+++ b/lib/certificate_utils.robot
@@ -167,6 +167,8 @@
     ${cert_list}=  Redfish_Utils.Get Member List  /redfish/v1/Managers/bmc/Truststore/Certificates
     FOR  ${cert}  IN  @{cert_list}
       Redfish.Delete  ${cert}  valid_status_codes=[${HTTP_NO_CONTENT}]
+      Log To Console  Wait Time started in seconds ${wait_time}
+      Sleep  ${wait_time}s
     END