Cleanup scratch container file
Cleanup scratch container file

If no --out is provide we use a scratch file for output container.  But
there is no reason to keep this; if the user wants a persistent file he
can specify --out.

Signed-off-by: Dave Heller <dadf76b92c028da3488e57973c6c8cd3d5ab990c@linux.vnet.ibm.com>

hellerda/sb-signing-utils,hellerda/sb-signing-utils