Fix object storage credentials.

[FernandoOjeda]

Fix object storage credentials #1127.

slcli object-storage --help

Options:
  -h, --help  Show this message and exit.

Commands:
  accounts    List object storage accounts.
  credential  Base command for all object storage credentials S3 related concerns
  endpoints   List object storage endpoints.

slcli object-storage credential --help

Usage: slcli object-storage credential [OPTIONS] COMMAND [ARGS]...

  Base command for all object storage credentials S3 related concerns

Options:
  -h, --help  Show this message and exit.

Commands:
  create  Create credentials for an IBM Cloud Object Storage Account
  delete  Delete the credential of an Object Storage Account.
  limit   Credential limits for this IBM Cloud Object Storage account.
  list    Retrieve credentials used for generating an AWS signature.

slcli object-storage credential create 11111

:.........:..........................................:......................:.........................:
:    id   :                 password                 :       username       :        type_name        :
:.........:..........................................:......................:.........................:
: 110111 : Bucbb2Fds3EIVto9f7JKYSwzig10Ej9Smw3qaYhE : n6Wk1MZkXuuHoGHfdwrs : S3 Compatible Signature :
:.........:..........................................:......................:.........................:

slcli object-storage credential delete --help

Usage: slcli object-storage credential delete [OPTIONS] IDENTIFIER

  Delete the credential of an Object Storage Account.

Options:
  -id, --credential_id INTEGER  This is the credential id associated with the volume
  -h, --help                    Show this message and exit.

slcli object-storage credential delete --credential_id 11111 22222

The credential was deleted successful

slcli object-storage credential limit 11111

:.......:
: limit :
:.......:
:   2   :
:.......:

slcli object-storage credential list 11111

:.........:..........................................:......................:.........................:
:    id   :                 password                 :       username       :        type_name        :
:.........:..........................................:......................:.........................:
: 1105111 : fuwrSDfddqSFsLiqOpCdFj9EuWtlGA1V9qLDEiSO : Bnn6JSDq6Uqert0elNLt : S3 Compatible Signature :
:  494222 : TGveOFhaBaDERDDey5onA2AHDVUCjSTHksCTiHyw : 9zC3dZGPORa5Eo7IIgkK : S3 Compatible Signature :
:.........:..........................................:......................:.........................:

[coveralls]

Coverage increased (+0.2%) to 92.01% when pulling 665ad1d on FernandoOjeda:fo_object_storage_credentials into cfab07e on softlayer:master.

[allmightyspiff]

just needs a few minor changes, looks great overall. Thanks.