Improve consistency of help strings

Fixes include rework of text, missing or extra spaces, wrong
capitalization and no sentence style capitalization.

Co-Authored-By: Diane Fleming <diane.fleming@rackspace.com>
Change-Id: I480a8f1816b0698a10165318fe25b4f58e8d2700
Correct spelling of logger for dispatcher.file

Closes-Bug: #1272176
Change-Id: Ia4d700869829142bd3b9e136b8a735756b92ea94
Merge "Improve consistency of help strings"
Use stevedore's make_test_instance

Replace the use of TestManager with make_test_instance
to get an instance of the type of manager expected.
The old TestManger class is deprecated.

Change-Id: I73f3202ac7a1420aaa303d5ea2e741b2fe5673e9
Partial-bug: #1273455
Merge "Correct spelling of logger for dispatcher.file"
Merge "Use stevedore's make_test_instance"