feat: make depositVerifier be updated right at newDepositVerifierMaturityTimestamp

All other places would make the update take effect right on the timestamp instead of timestamp + 1.
This change makes it to be consistent with others.

Author: boolafish

plasma_framework/contracts/src/vaults/Vault.sol

@@ -63,10 +63,10 @@ contract Vault is Operated {
      * @return contract address of deposit verifier.
      */
     function getEffectiveDepositVerifier() public view returns (address) {
-        if (now > newDepositVerifierMaturityTimestamp) {
-            return depositVerifiers[1];
-        } else {
+        if (now < newDepositVerifierMaturityTimestamp) {
             return depositVerifiers[0];
+        } else {
+            return depositVerifiers[1];
         }
     }
 }

plasma_framework/test/src/utils/BondSize.test.js

@@ -2,7 +2,7 @@ const BondSizeMock = artifacts.require('BondSizeMock');
 const { BN, expectRevert, time } = require('openzeppelin-test-helpers');
 const { expect } = require('chai');
 
-contract.only('BondSize', () => {
+contract('BondSize', () => {
     const WAITING_PERIOD = time.duration.days(2);
     const HALF_WAITING_PERIOD = WAITING_PERIOD.divn(2);
 

plasma_framework/test/src/vaults/EthVault.test.js

@@ -152,7 +152,7 @@ contract('EthVault', ([_, alice]) => {
             expect(await this.ethVault.getEffectiveDepositVerifier()).to.equal(this.currentDepositVerifier);
             await expectEvent.inLogs(tx.logs, 'SetDepositVerifierCalled', { nextDepositVerifier: newDepositVerifier.address });
 
-            await time.increase(MIN_EXIT_PERIOD + 1);
+            await time.increase(MIN_EXIT_PERIOD);
             expect(await this.ethVault.getEffectiveDepositVerifier()).to.equal(newDepositVerifier.address);
         });
     });