enable full linter across the codebase (#9620)

enable linter using golangci-lint across
codebase to run a bunch of linters together,
we shall enable new linters as we fix more
things the codebase.

This PR fixes the first stage of this
cleanup.

pkg/s3select/csv/args.go

@@ -26,9 +26,8 @@ import (
 )
 
 const (
-	none   = "none"
-	use    = "use"
-	ignore = "ignore"
+	none = "none"
+	use  = "use"
 
 	defaultRecordDelimiter      = "\n"
 	defaultFieldDelimiter       = ","
@@ -36,7 +35,6 @@ const (
 	defaultQuoteEscapeCharacter = `"`
 	defaultCommentCharacter     = "#"
 
-	always   = "always"
 	asneeded = "asneeded"
 )
 

pkg/s3select/csv/errors.go

@@ -43,24 +43,6 @@ func (err *s3Error) Error() string {
 	return err.message
 }
 
-func errInvalidFileHeaderInfo(err error) *s3Error {
-	return &s3Error{
-		code:       "InvalidFileHeaderInfo",
-		message:    "The FileHeaderInfo is invalid. Only NONE, USE, and IGNORE are supported.",
-		statusCode: 400,
-		cause:      err,
-	}
-}
-
-func errInvalidQuoteFields(err error) *s3Error {
-	return &s3Error{
-		code:       "InvalidQuoteFields",
-		message:    "The QuoteFields is invalid. Only ALWAYS and ASNEEDED are supported.",
-		statusCode: 400,
-		cause:      err,
-	}
-}
-
 func errCSVParsingError(err error) *s3Error {
 	return &s3Error{
 		code:       "CSVParsingError",