Adding retries to handle the following types of failure:
1. Create communication session failed - Failed to create session.
2. Unable to establish Redfish client connections to BMC at <ip address>
(Server not reachable, return code: 503).
3. Fail to set System Power State to On/Off.
Test Plan:
PASS: Retries work properly when session creation fails.
PASS: Retries work properly when Unable to establish Redfish client
connection to BMC.
PASS: Retries work properly when returning 500 error in the "Power Off
Host" stage.
PASS: rvmc script executed successfully without above errors.
Story: 2010144
Task: 46761
Signed-off-by: Li Zhu <li.zhu@windriver.com>
Change-Id: I6bb2e0822a51770b181181b49a86fb51d6dca18b
eaf07202a9