privilege: fix update privilege error for release-2.1

[haplone]

What problem does this PR solve?

issue10028

update ap.record t inner join tp.record tt on t.id=tt.id  set t.name=tt.name;

ERROR 1105 (HY000): privilege check fail

What is changed and how it works?

only use modified table name for update privilege check in planner/core/logical_plan_builder.go#buildUpdate

Check List

Tests

• Unit test

Code changes

Side effects

Related changes

[haplone]

@imtbkcat
I found branch release 2.1 on tidb has an error, if it is fixed ,we could solve this issue in release 2.1 by cherry pick :
https://github.com/pingcap/tidb/blob/release-2.1/planner/core/logical_plan_builder.go#L2153

func (b *planBuilder) buildUpdate(update *ast.UpdateStmt) (Plan, error) {
       // ...
        for _, t := range tableList {
		dbName := t.Schema.L
		if dbName == "" {
			dbName = b.ctx.GetSessionVars().CurrentDB
		}
		// the mysql.UpdatePriv should be mysql.SelectPriv
		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.UpdatePriv, dbName, t.Name.L, "")
	}

[zz-jason]

@haplone Is this problem existed in the master branch?

[haplone]

@haplone Is this problem existed in the master branch?

Yes, this problem existed in the master branch.

we could see issue10028 and PR10085

@zz-jason

[haplone]

@zz-jason

this problem exists in the master branch

PTAL

[zz-jason]

@zz-jason

this problem exists in the master branch

PTAL

OK, How about getting the master PR merged first then do the cherry-pick

[qw4990]

@haplone PTAL, could you please fix these conflicts and help us merge this PR into release 2.1?