cgroup: Set "soft" mode by default

In criu 1.6 if no --manage-cgroups option been specified
we still restore default (known) properties. But in commit
c7d646af we've enhanced its semantics occasionally break
backward compatibility: if no --manage-cgroups passed at all
it's assumed that one asks to not touch cgroups at all on
restore. To restore old behaviour setup "soft" mode by
default.
Reported-by: Andrew Vagin <avagin@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/cr_options.h

@@ -31,7 +31,7 @@ struct cg_root_opt {
 #define CG_MODE_FULL		(1u << 3)
 #define CG_MODE_STRICT		(1u << 4)
 
-#define CG_MODE_DEFAULT		(CG_MODE_IGNORE)
+#define CG_MODE_DEFAULT		(CG_MODE_SOFT)
 
 struct cr_options {
 	int			final_state;