Adjust certificate install wait time to prevent bmcweb stopping

Changes:
     - provision user to key in the with wait_time variable
       example:  -v wait_time:180

bmcweb.service: Start request repeated too quickly and hits the
limit and breaks the bmweb service until next BMC reset or restart
the bmcweb service manually.

This increases the test execution, however, there is no better way
to handle this in test cases.

Tested:
      Ran successfully redfish/managers/test_certificate.robot

Change-Id: I965f8a09d95260c8c7c2f08c655125544c630251
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/certificate_utils.robot b/lib/certificate_utils.robot
index db1c233..febe976 100755
--- a/lib/certificate_utils.robot
+++ b/lib/certificate_utils.robot
@@ -5,6 +5,10 @@
 Resource       rest_client.robot
 Resource       resource.robot
 
+*** Variables ***
+
+# Default wait sync time for certificate install and restart services.
+${wait_time}    30
 
 *** Keywords ***
 
@@ -275,7 +279,9 @@
     Logging  Installed certificate id: ${cert_id}
 
     # Adding delay after certificate installation.
-    Sleep  30s
+    # Lesser wait timing causes bmcweb to restart quickly and breaks the web services.
+    Log To Console  Wait Time started in seconds ${wait_time}
+    Sleep  ${wait_time}s
 
     ${cert_file_content}=  OperatingSystem.Get File  ${cert_file_path}
     ${bmc_cert_content}=  Run Keyword If  '${expected_status}' == 'ok'  redfish_utils.Get Attribute