NativeConvert.ToDateTime handles nanoseconds incorrectly

[rosenqui-cysiv]

NativeConvert.ToDateTime should divide the nanoTime component by 1000000 when converting to milliseconds rather than 1000.

From Mono.Unix.Native/NativeConvert.cs:

public static DateTime ToDateTime (long time, long nanoTime)
{
    return FromTimeT (time).AddMilliseconds (nanoTime / 1000);
}