fs: remove unnecessary Seek call on log file

We were seeing a (non-fatal) error in our logs:
```
Failed to seek log file to end: seek /proc/1/fd/1: illegal seek
```

Because we open the log file with O_APPEND,
we don't need to manually seek to the end.
As https://pkg.go.dev/os#File.Seek also confirms
that the behavior of `Seek` is not specified
if the file has been opened with O_APPEND,
remove the `Seek` call.

fs/log/log.go

@@ -216,10 +216,6 @@ func InitLogging() {
 			if err != nil {
 				fs.Fatalf(nil, "Failed to open log file: %v", err)
 			}
-			_, err = f.Seek(0, io.SeekEnd)
-			if err != nil {
-				fs.Errorf(nil, "Failed to seek log file to end: %v", err)
-			}
 			redirectStderr(f)
 			w = f
 		} else {