Testnet macOS build crashes on block 196636

[abitmore]

Bug Description

Testnet macOS build (built with bitshares/bitshares-gitian#38) crashes when applying block 196636.

There is a proposal_update operation in the block.

locked >>> get_block 196636
{
  "previous": "0003001bbf05559742344771af781ab341917bda",
  "timestamp": "2016-01-30T22:23:55",
  "witness": "1.6.10",
  "transaction_merkle_root": "e119ae2a939a63b575472862612ccbed67907a3e",
  "extensions": [],
  "witness_signature": "1f0e13d748f9991ef797802f2019b0a2adbfa91852f4e6397dde1f67a294611e3b24152dd22b411670d0c434e389b5bde663f86a80e0d2b48b86d225fb9c810dab",
  "transactions": [{
      "ref_block_num": 27,
      "ref_block_prefix": 2538931647,
      "expiration": "2016-01-30T22:24:20",
      "operations": [[
          23,{
            "fee": {
              "amount": 2000000,
              "asset_id": "1.3.0"
            },
            "fee_paying_account": "1.2.41",
            "proposal": "1.10.8",
            "active_approvals_to_add": [
              "1.2.50"
            ],
            "active_approvals_to_remove": [],
            "owner_approvals_to_add": [],
            "owner_approvals_to_remove": [],
            "key_approvals_to_add": [],
            "key_approvals_to_remove": [],
            "extensions": []
          }
        ]
      ],
      "extensions": [],
      "signatures": [
        "1f032c2b1fd0eeb5a6e9be17faa06316b56927b301f62c8fe940c05d51a313bf7c056d931e53812319c1fe6a7b50e18e73a5353497e12212458b88e4ebd6d409cd",
        "1f45e75f37ba76255f73daccb5290efe91e9ae47edaf62bf392c63bd045f30507f4aec65eb5505523cca3e40cbedc3f82311edc6d36fb4905ab7e67bff2cdd296e"
      ],
      "operation_results": [[
          0,{}
        ]
      ]
    }
  ],
  "block_id": "0003001c9d4e48af3b401e4943e7801d2980f5ba",
  "signing_key": "TEST829GU3MErA1a7biLT6SYeFXcXkURsLXxZDMyAh4V31cdVbiQ4P",
  "transaction_ids": [
    "9e0400874dc4c1b8870db751101f58eea52dbcdb"
  ]
}

The crash occurs when checking authorities of the proposal:

bitshares-core/libraries/chain/proposal_evaluator.cpp

Lines 390 to 391 in e767c38

	if( (d.head_block_time() < fc::time_point_sec(HARDFORK_TEST_201706_TIME) && _testnet_old_is_authorized(*_proposal, d))
	|| (d.head_block_time() >= fc::time_point_sec(HARDFORK_TEST_201706_TIME) && _proposal->is_authorized_to_execute(d)) )

Impacts
Describe which portion(s) of BitShares Core may be impacted by this bug. Please tick at least one box.

• API (the application programming interface)
• Build (the build process or something prior to compiled code)
• CLI (the command line wallet)
• Deployment (the deployment process after building such as Docker, Travis, etc.)
• DEX (the Decentralized EXchange, market engine, etc.)
• P2P (the peer-to-peer network for transaction/block propagation)
• Performance (system or user efficiency, etc.)
• Protocol (the blockchain logic, consensus, validation, etc.)
• Security (the security of system or user data, etc.)
• UX (the User Experience)
• Other (please add below)

CORE TEAM TASK LIST

• Evaluate / Prioritize Bug Report
• Refine User Stories / Requirements
• Define Test Cases
• Design / Develop Solution
• Perform QA/Testing
• Update Documentation

[abitmore]

Fixed by #2200.