Let ErrnoMaintainer restore errno unconditionally.

* we never want to let ICU calls change the errno at all, so we always
  restore it to the value it had before entering ICU (not just if it
  was 0)

headers/private/libroot/ErrnoMaintainer.h

@@ -25,9 +25,9 @@ public:
 
 	~ErrnoMaintainer()
 	{
-		if (errno != 0 && fErrnoUponEntry == 0)
-			errno = 0;
+		errno = fErrnoUponEntry;
 	}
+
 private:
 	int fErrnoUponEntry;
 };