scratchtool.c: fix resource leak and error handling

Check the result of rados_ioctx_create()before using io_ctx.
Free io_ctx where needed. Fix messages at the end of testrados().

CID 1219613 (#1 of 1): Resource leak (RESOURCE_LEAK)
 leaked_storage: Variable io_ctx going out of scope leaks the
 storage it points to.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>