Since iRMC S6 2.00, iRMC firmware doesn't support HTTP
connection to REST API.
To deal with this firmware incompatibility, this commit
adds verify step to check connection to REST API and adds
node vendor passthru to fetch&cache version of iRMC firmware.
Story: 2010396
Task: 46745
Change-Id: Ib04b66b0c7b1ef1c4175841689c16a7fbc0b1e54