SystemControl: Call the right function in release() and releaseAll()

[algernon]

Since ab9702352f09f4f4ceee0ba639f872d00df06e93, SystemControl_::begin() is a no-op, calling it in release() and releaseAll() is not doing what it did prior to that commit: call end(), which is what the release functions really wanted to do in the first place.

Lets do the right thing then, and call end().

[obra]

to make the code clearer, the release code should be in release instead of end. then end should call release

[algernon]

Updated & force pushed