go: Fix things staticcheck complains about

Client: go

Staticcheck is the recommended replacement of the frozen and deprecated
official golint linter [1].

Fix the things it complained about (or add lint:ignore directive) in:

- lib/go/thrift
- lib/go/test/tests
- tutorial/go/src
- test/go/src
- compiler generated code

The majority of the fixes are in the following categories:

- Use of deprecated function (mainly the TConfiguration related ones)
- Redundant break in switch cases
- Unused and unexported variables/fields/functions

Also in the same spirit as fb539ae, remove the error return from
NewTSSLSocket as it can never be non-nil.

This change will be cherry-picked into 0.15.0 branch after merged.

[1]: https://groups.google.com/g/golang-nuts/c/rCP70Aq_tBc
diff --git a/tutorial/go/src/handler.go b/tutorial/go/src/handler.go
index 7645fc2..a9edd26 100644
--- a/tutorial/go/src/handler.go
+++ b/tutorial/go/src/handler.go
@@ -51,13 +51,10 @@
 	switch w.Op {
 	case tutorial.Operation_ADD:
 		val = w.Num1 + w.Num2
-		break
 	case tutorial.Operation_SUBTRACT:
 		val = w.Num1 - w.Num2
-		break
 	case tutorial.Operation_MULTIPLY:
 		val = w.Num1 * w.Num2
-		break
 	case tutorial.Operation_DIVIDE:
 		if w.Num2 == 0 {
 			ouch := tutorial.NewInvalidOperation()
@@ -67,7 +64,6 @@
 			return
 		}
 		val = w.Num1 / w.Num2
-		break
 	default:
 		ouch := tutorial.NewInvalidOperation()
 		ouch.WhatOp = int32(w.Op)
@@ -93,7 +89,7 @@
 
 func (p *CalculatorHandler) GetStruct(ctx context.Context, key int32) (*shared.SharedStruct, error) {
 	fmt.Print("getStruct(", key, ")\n")
-	v, _ := p.log[int(key)]
+	v := p.log[int(key)]
 	return v, nil
 }