Improve the flasher deployment method

This will:
* allow to record results for each command
* use shell syntax (with pipes)

This will make MuxPi or SDMux integration easier.

Signed-off-by: Rémi Duraffort <remi.duraffort@linaro.org>
12 jobs for sdmux in 3 minutes and 1 second (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #23249
amd64
dispatcher-debian-10

00:02:43

failed #23247
amd64
dispatcher-debian-9

00:03:01

passed #23250
amd64
server-debian-10

00:02:04

passed #23248
amd64
server-debian-9

00:02:32

 
  Analyze
skipped #23251
amd64
black
skipped #23252
amd64
codestyle
skipped #23253
dind amd64 allowed to fail
sast
 
  Build
skipped #23256
amd64
amd64/pkg-debian-10
skipped #23255
amd64
amd64/pkg-debian-9
skipped #23254
amd64
doc
 
  Docker
skipped #23257
dind amd64
amd64/lava-dispatcher
skipped #23258
dind amd64
amd64/lava-server
 
Name Stage Failure
failed
dispatcher-debian-9 Test
WC1 /builds/ivoire/lava/lava_dispatcher/tests/test_multinode.py cannot collect test class 'TestError' because it has a __init__ constructor
WC1 /builds/ivoire/lava/lava_dispatcher/tests/test_multinode.py cannot collect test class 'TestCoordinator' because it has a __init__ constructor
WC1 /builds/ivoire/lava/lava_dispatcher/tests/test_repeat.py cannot collect test class 'TestShellRetry' because it has a __init__ constructor
WC1 /builds/ivoire/lava/lava_dispatcher/tests/test_test_shell.py cannot collect test class 'TestError' because it has a __init__ constructor
==== 1 failed, 340 passed, 7 skipped, 13 pytest-warnings in 159.98 seconds =====
Uploading artifacts...
dispatcher.xml: found 1 matching files
Uploading artifacts to coordinator... ok
id=23247 responseStatus=201 Created token=_Woxo3_M
ERROR: Job failed: exit code 1
failed
dispatcher-debian-10 Test
  /usr/lib/python3/dist-packages/jinja2/lexer.py:587: DeprecationWarning: invalid escape sequence '\s'
.decode('unicode-escape')

-- Docs: https://docs.pytest.org/en/latest/warnings.html
======== 1 failed, 338 passed, 9 skipped, 22 warnings in 138.53 seconds ========
Uploading artifacts...
dispatcher.xml: found 1 matching files
Uploading artifacts to coordinator... ok
id=23249 responseStatus=201 Created token=3yHSuG8u
ERROR: Job failed: exit code 1