fix_test_add_rm_committee_members

[saratomaz]

data returned by query committee-state:

{
    "committee": {
        "keyHash-0daa16ed59809a111ae2b7189f69631422562fabf5aa1a6f6f4a0e58": {
            "expiration": 10000,
            "hotCredsAuthStatus": {
                "contents": {
                    "keyHash": "2a7a8a3038137d749bce268961a7375417dfdf856a4388e2ba7b4e38"
                },
                "tag": "MemberAuthorized"
            },
            "nextEpochChange": {
                "tag": "NoChangeExpected"
            },
            "status": "Active"
        },
     ...
    "epoch": 52,
    "threshold": 0.6
}