TUN-2243: Revert "STOR-519: Add db-connect, a SQL over HTTPS server"

This reverts commit 5da2109811.

vendor/github.com/kshvakov/clickhouse/clickhouse_ping.go

@@ -1,28 +0,0 @@
-package clickhouse
-
-import (
-	"context"
-	"database/sql/driver"
-
-	"github.com/kshvakov/clickhouse/lib/protocol"
-)
-
-func (ch *clickhouse) Ping(ctx context.Context) error {
-	return ch.ping(ctx)
-}
-
-func (ch *clickhouse) ping(ctx context.Context) error {
-	if ch.conn.closed {
-		return driver.ErrBadConn
-	}
-	ch.logf("-> ping")
-	finish := ch.watchCancel(ctx)
-	defer finish()
-	if err := ch.encoder.Uvarint(protocol.ClientPing); err != nil {
-		return err
-	}
-	if err := ch.encoder.Flush(); err != nil {
-		return err
-	}
-	return ch.process()
-}