shell: Added minor changes to `fs.meta.save`
shell: Added minor changes to `fs.meta.save`

* added an option to set the output file name
* added an option to see verbose output, default to non-verbose mode

related to: https://github.com/chrislusf/seaweedfs/issues/1019

chrislusf/seaweedfs,chrislusf/seaweedfs,chrislusf/seaweedfs,chrislusf/seaweedfs