cleanup pyc files between running pytest

this is need to avoid problem sometimes tests are run inside docker
container and sometimes local.

Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/_pytest/config/__init__.py", line 409, in _importconftest
mod = conftestpath.pyimport()
File "/usr/lib/python2.7/dist-packages/py/_path/local.py", line 686, in pyimport
raise self.ImportMismatchError(modname, modfile, self)
ImportMismatchError: ('conftest', '/beremiz/tests/tools/conftest.py', local('/home/developer/beremiz/tests/tools/conftest.py'))
ERROR: could not load /home/developer/beremiz/tests/tools/conftest.py

#!/bin/sh

cleanup()
{
    find ./tests/tools -name '*.pyc' -delete
}

LC_ALL=ru_RU.utf-8

export DISPLAY=:42
Xvfb $DISPLAY -screen 0 1280x1024x24 &
sleep 1


cleanup

ret=0
DELAY=400
KILL_DELAY=$(($DELAY + 30))
timeout -k $KILL_DELAY $DELAY pytest --timeout=10 ./tests/tools
ret=$?

cleanup


pkill -9 Xvfb

exit $ret