LXC: fix memory leak in lxcContainerMountFSBlockAuto

we forgot to free fslist,just add VIR_FREE(fslist).
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

src/lxc/lxc_container.c

@@ -895,6 +895,7 @@ retry:
 
 cleanup:
     VIR_FREE(line);
+    VIR_FREE(fslist);
     VIR_FORCE_FCLOSE(fp);
     return ret;
 }