Add ability to clean peppervenv

Currently by default pepper will use old venv
with old token which can expire.

This commit adds ability to specify venv clean flag,
but keeps default behavior the same - not do cleaning.

Change-Id: I916888b66a71a086aa39fc4f568bb1ca4bcbb65b
Related-Prod: https://mirantis.jira.com/browse/PROD-16019
1 file changed