also put INSERT_PRODUCTS_PATH in erp5testrunner's sys.path

Tests directory of inserted paths also needs to be in sys.path so that tests
can import other tests.
each promise should have a different path.
use memory-based kumofs instead of memcached to have no limitation for key length and data size.
Merge branch 'master' into erp5-component
Add backward compatibility about Partition.getInstanceGuid().

Old versions of slapproxy/slapos master don't know it.
Catching it here so that we have a chance to debug problems in SRs.
Merge branch 'erp5-component' into erp5