Repalce to "tempest account-generator"

As in main function:301
LOG.warning("Use of: 'tempest-account-generator' is deprecated, "
            "please use: 'tempest account-generator'")
We should use "tempest account-generator" in the other place of
the code, otherwise will cause confusion.

Change-Id: I74fdc19e1025e9ecb168dc5157a1bbec040126d8
1 file changed