ostestr is no longer installed by default by infra and will be totally
removed longer term; stestr [1] is its replacement.
This is the reason out gate is failing with the following today:
nsx/tools/ostestr_compat_shim.sh: ostestr: not found
This patch moves us to stestr by:
- Updating tox.ini to use stestr rather than call ostestr_compat_shim.sh
and in turn ostestr.
- Removing ostestr_compat_shim.sh as its no longer used.
For more details on stestr see [1].
Also note that this is a quick migration to stestr to get the gate
working; additional tweaks may come up.
[1] http://stestr.readthedocs.io/en/latest/MANUAL.html
Change-Id: I9a871d3542c2f2615d757c0009ea3d6695f0e3f7
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