message: Update error.rs
  Change the error message to make it clear that the Credential Def is on the user's local wallet, not on the public ledger.
diff: @@ -50,7 +50,7 @@ pub static UNKNOWN_LIBINDY_ERROR: Error = Error{code_num: 1035, message: "Unknow
  pub static INVALID_CREDENTIAL_DEF_JSON: Error = Error{code_num: 1036, message: "Credential Def not in valid json"};
  pub static INVALID_CREDENTIAL_DEF_HANDLE: Error = Error{code_num: 1037, message: "Invalid Credential Definition handle"};
  pub static TIMEOUT_LIBINDY_ERROR: Error = Error{code_num: 1038, message: "Waiting for callback timed out"};
  -pub static CREDENTIAL_DEF_ALREADY_CREATED: Error = Error{code_num: 1039, message: "Can't create, Credential Def already on ledger"};
  +pub static CREDENTIAL_DEF_ALREADY_CREATED: Error = Error{code_num: 1039, message: "Can't create, Credential Def already exists in wallet"};
  pub static INVALID_SCHEMA_SEQ_NO: Error = Error{code_num: 1040, message: "No Schema for that schema sequence number"};
  pub static INVALID_SCHEMA_CREATION: Error = Error{code_num: 1041, message: "Could not create schema"};
  pub static INVALID_SCHEMA_HANDLE: Error = Error{code_num: 1042, message: "Invalid Schema Handle"};
  