[compress]Default compression level use
- add test casees for a module without default.Using default
compression level.
- Discuss with Fabio, invalid compression level not the knet
responsible for, so error logged. But if compress success but
dstLen larger than srcLen, defualt compression level will be
used, because the request level is not effective.
Signed-off-by: yuan ren <yren@suse.com>