busybox: add sysctl.conf.sample
Revert "transmission: net.core.{r,w}mem.max *workaround for uTP"

This reverts commit 2cf0e0be30ebd6f6e73f1fb78adc897f1cb3ecd4.
Revert "transmission: uTP is now disabled by default. add option to enable it."

This reverts commit 0b3c1a4e6730b9884a1682cd503ca270dc0d02df.