tox: Drop redundant injection of VIRTUAL_ENV variable
The environment variable is set automatically. cf. https://github.com/tox-dev/tox/commit/be5373bab Change-Id: I125036d2a19759646933e3f70a1567a01cc8cfa2 Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>
This commit is contained in: