Fix EventLog teardown

Changes:
   - Take redfish connection since power on/off keywords closes out sessions.

Change-Id: Ic2457a99b0fe647c5959787d01a1219587073b3a
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/systems/eventlog/test_event_logging.robot b/redfish/systems/eventlog/test_event_logging.robot
index f8c7abc..5e66b2d 100644
--- a/redfish/systems/eventlog/test_event_logging.robot
+++ b/redfish/systems/eventlog/test_event_logging.robot
@@ -295,6 +295,7 @@
     [Documentation]  Do the post test teardown.
 
     FFDC On Test Case Fail
+    Redfish.Login
     Redfish Purge Event Log