archive-*-source.bbclass: fix scripts_with_logs build error

archive-*-source.bbclass: fix scripts_with_logs build error

Log and script archives are only generated when explicitly enabled by
setting the environment variable SOURCE_ARCHIVE_LOG_WITH_SCRIPTS to
'logs_with_scripts'. When left disabled, the path specified to be
handled by sstate is never created, resulting in a build error.

Only attempt to archive scripts and logs when explicitly enabled.

Signed-off-by: Kevin Strasser <kevin.strasser@linux.intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>