ImportError: No module named pytest during run_system_test.py run

[Ann Taraday]

Reproduced on https://product-ci.infra.mirantis.net/view/10.0/job/10.0.main.ubuntu.bvt_2/519/console and https://product-ci.infra.mirantis.net/view/10.0/job/10.0.main.ubuntu.smoke_neutron/519/console

Deployment failed with

+ python run_system_test.py run -q --nologcapture --with-xunit --group=bvt_2
Traceback (most recent call last):
  File "run_system_test.py", line 6, in <module>
    import pytest
ImportError: No module named pytest
+ ec=1
+ [ != no ]
+ find /home/jenkins/workspace/10.0.main.ubuntu.bvt_2/logs -name fail*.tar.[gx]z -type f
+ [ != yes ]
+ [ no = yes ]
+ dos.py destroy 10.0.main.ubuntu.bvt_2.519
Enviroment with name 10.0.main.ubuntu.bvt_2.519 doesn't exist.
+ exit 1
Build step 'Execute shell' marked build as failure
Archiving artifacts
Recording test results
ERROR: Publisher 'Publish JUnit test result report' failed: No test report files were found. Configuration error?
Performing Post build task...
Could not match :Build timed out : False
Logical operation result is FALSE
Skipping script : #!/bin/bash

set -ex

source "${WORKSPACE}/${DOS_ENV_NAME_PROPS_FILE:=.dos_environment_name}"
source "${VENV_PATH}/bin/activate"
dos.py destroy "${ENV_NAME}"

END OF POST BUILD TASK : 0
[description-setter] Could not determine description.
Email was triggered for: Failure - Any
Email was triggered for: Failure - Still
Trigger Failure - Any was overridden by another trigger and will not send an email.
Sending email for trigger: Failure - Still
Sending email to: <email address hidden>
No emails were triggered.
Finished: FAILURE