Remove the delegate from the burrow representation

[gkaracha]

Since set_burrow_delegate merely propagates requests to change the delegate to the burrow contract. On top of reducing byte counts and gas costs, I expect this change to reduce storage representation differences between FA2/tez collateral (that is, w.r.t. #213).

[gkaracha]

The bot is acting up again so we cannot see the differences in byte counts and gas costs but I'm pretty sure they both drop.

[dorranh]

LGTM! It's nice to be able to remove some extra state which we weren't using anymore.

[gkaracha]

Pasting here the stat difference myself, just for completeness.

$ diff stats-master/entrypoint-sizes.json stats-238/entrypoint-sizes.json

<   "activate_burrow": 1292,
>   "activate_burrow": 1274,
<   "burn_kit": 1561,
>   "burn_kit": 1527,
<   "cancel_liquidation_slice": 12177,
>   "cancel_liquidation_slice": 12157,
<   "create_burrow": 1097,
>   "create_burrow": 1079,
<   "deactivate_burrow": 1603,
>   "deactivate_burrow": 1581,
<   "deposit_collateral": 1163,
>   "deposit_collateral": 1145,
<   "mark_for_liquidation": 17093,
>   "mark_for_liquidation": 17061,
<   "mint_kit": 1588,
>   "mint_kit": 1550,
<   "set_burrow_delegate": 1059,
>   "set_burrow_delegate": 490,
<   "touch": 56614,
>   "touch": 56574, 
<   "touch_burrow": 660,
>   "touch_burrow": 642,
<   "touch_liquidation_slices": 14508,
>   "touch_liquidation_slices": 14474,
<   "withdraw_collateral": 1488
>   "withdraw_collateral": 1468

$ diff stats-master/gas-costs.json stats-238/gas-costs.json

<     "touch": 538767,
>     "touch": 537238,
<     "remove_liquidity": 73903,
>     "remove_liquidity": 73590,
<     "add_liquidity": 73651,
>     "add_liquidity": 73337,
<     "buy_kit": 69637,
>     "buy_kit": 69323,
<     "sell_kit": 68764,
>     "sell_kit": 68450,
<     "deactivate_burrow": 59288,
>     "deactivate_burrow": 58783,
<     "withdraw_collateral": 58284,
>     "withdraw_collateral": 57802,
<     "set_burrow_delegate": 54691,
>     "set_burrow_delegate": 49911,
<     "activate_burrow": 54542,
>     "activate_burrow": 54073,
<     "deposit_collateral": 53735,
>     "deposit_collateral": 53270,
<     "mint_kit": 51869,
>     "mint_kit": 51241,
<     "burn_kit": 51613,
>     "burn_kit": 51014,
<     "create_burrow": 48918,
>     "create_burrow": 48469,
<     "touch_burrow": 44409,
>     "touch_burrow": 43897,
<     "update_operators": 41672,
>     "update_operators": 41363,
<     "transfer": 39928
>     "transfer": 39622

$ diff stats-master/test-coverage.json stats-238/test-coverage.json

<   "TOTAL": 93.96,
>   "TOTAL": 93.94,
<   "burrow.ml": 96.26,
>   "burrow.ml": 96.21,
<   "checker.ml": 90.08,
>   "checker.ml": 90.04,

[gkaracha]

LGTM! It's nice to be able to remove some extra state which we weren't using anymore.

Yeah, the less code the better! 😄