Fix panic (not fatal) on connection drops (#13811)
Fix panic (not fatal) on connection drops (#13811)

Fix more regressions from #13597 with double closed channels.

```
panic: "POST /minio/storage/data/distxl-plain/s1/d2/v42/createfile?disk-id=c789f7e1-2b52-442a-b518-aa2dac03f3a1&file-path=f6161668-b939-4543-9873-91b9da4cdff6%2F5eafa986-a3bf-4b1c-8bc0-03a37de390a3%2Fpart.1&length=2621760&volume=.minio.sys%2Ftmp": send on closed channel
goroutine 1977 [running]:
runtime/debug.Stack()
        c:/go/src/runtime/debug/stack.go:24 +0x65
github.com/minio/minio/cmd.setCriticalErrorHandler.func1.1()
        d:/minio/minio/cmd/generic-handlers.go:468 +0x8e
panic({0x2928860, 0x4fb17e0})
        c:/go/src/runtime/panic.go:1038 +0x215
github.com/minio/minio/cmd.keepHTTPReqResponseAlive.func2({0x4fe4ea0, 0xc02737d8a0})
        d:/minio/minio/cmd/storage-rest-server.go:818 +0x48
github.com/minio/minio/cmd.(*storageRESTServer).CreateFileHandler(0xc0015a8510, {0x50073e0, 0xc0273ec460}, 0xc029b9a400)
        d:/minio/minio/cmd/storage-rest-server.go:334 +0x1d2
net/http.HandlerFunc.ServeHTTP(...)
        c:/go/src/net/http/server.go:2046
github.com/minio/minio/cmd.httpTraceHdrs.func1({0x50073e0, 0xc0273ec460}, 0x0)
        d:/minio/minio/cmd/handler-utils.go:372 +0x53
net/http.HandlerFunc.ServeHTTP(0x5007380, {0x50073e0, 0xc0273ec460}, 0x10)
        c:/go/src/net/http/server.go:2046 +0x2f
github.com/minio/minio/cmd.addCustomHeaders.func1({0x5007380, 0xc0273dcf00}, 0xc0273f7340)
```

Reverts but adds write checks.
krisis/minio,donatello/minio,minio/minio,minio/minio,krisis/minio,balamurugana/minio,balamurugana/minio,vadmeste/minio,vadmeste/minio,donatello/minio