Incorrect variable name in some exception

[Yusuke Hayashi]

Incorrect variable names 'msg_fmt' are used instead of 'message' in some exception classes,
and exception messages are not shown as expected due to this incorrect names.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/215388

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/215388
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=4f8224fe279933ff3139bd2287b314c963c50d9d
Submitter: Jenkins
Branch: master

commit 4f8224fe279933ff3139bd2287b314c963c50d9d
Author: Yusuke Hayashi <email address hidden>
Date: Thu Aug 20 20:36:06 2015 +0900

    Fix incorrect variable name in some exception class

    At manila.exception:
    msg_fmt => message

    Reason:
    When msg_fmt is passed to parent class, the information is not shown
    because parent class expect variable 'message'.

    Change-Id: I3e1346e7d6258eac4a5df965e4315090fbfcda0b
    Closes-Bug: #1487247