fix minor issues in test runner scripts on device#4542

Merged

d-a-v merged 2 commits intoesp8266:masterfrom

Mar 21, 2018

Commits on Mar 21, 2018

tests/device/Makefile: use bourne shell compatible "." instead ot "source" (ubuntu's dash does not understand it)
d-a-v
committed
tests/device: make BEGINTIMEOUT a new error return value instead of a test-process-breaking exception
d-a-v
committed