Adapt zdtm for python3 compatibility

As python3 imports are working a bit differently the structure of the
imported files needs to change. Instead of having symlinks to criu.py
and rpc_pb2.py which does not match the import structure just create
symlink to ../lib/py (like crit) to make zdtm usable again with the
python3 compatibility.
Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

test/criu.py

-../lib/py/criu.py
\ No newline at end of file

test/pycriu

+../lib/py/
\ No newline at end of file

test/rpc_pb2.py

-../lib/py/rpc_pb2.py
\ No newline at end of file

test/zdtm.py

@@ -20,7 +20,7 @@ import fcntl
 import errno
 import datetime
 import yaml
-import criu as crpc
+import pycriu as crpc
 
 os.chdir(os.path.dirname(os.path.abspath(__file__)))