
  "wallet_name" : "str",       (string) The name of the primary migrated wallet
  "watchonly_name" : "str",    (string, optional) The name of the migrated wallet containing the watchonly scripts
  "solvables_name" : "str",    (string, optional) The name of the migrated wallet containing solvable but not watched scripts
  "backup_path" : "str"        (string) The location of the backup of the original wallet
}

Examples:
> bitcoin-cli migratewallet 
> curl --user myusername --data-binary '{"jsonrpc": "1.0",