Gracefully handle BMCs returning "Insufficient resources"

[gebn]

bmc_exporter/collector/collector.go

Line 376 in 6275ae2

if err := bmc.ValidateResponse(c.session.SendCommand(cmdFirstCtx, cmd)); err != nil {

If we decode the command response successfully, we don't need to tear down the session, even if the completion code is non-normal, as the session is still in a good state. We will want to retry in the case of insufficient resources, otherwise return the error up, as we can't move past it. Doing this will invalidate this comment:

bmc_exporter/collector/collector.go

Line 249 in 6275ae2

// we don't continue on error, as the only reason for an error is ctx

Perhaps modify that function to keep returning early iff the context has expired.

[gebn]

Test this - overwhelm a BMC such that it returns a non-normal completion code.