two chroot related fixes

- Pass SCR root path to stdio agents [bnc#879365](https://bugzilla.novell.com/show_bug.cgi?id=879365).
- If aborting on a SCRAgent::targetPath assertion, log it [bnc#891053](https://bugzilla.novell.com/show_bug.cgi?id=891053)

why double quotes is needed here?