Add python.runCmd() to get more details from shell commands

- always print the executing command to control
  the pipeline execution
- always allows to get the stdout/stderr/status
  in the result, even with enabled console enabled
- throws an exception with stderr content, so
  it could be read from the job status and processed

Related task: https://mirantis.jira.com/browse/PROD-31620

Change-Id: I7b0d6ba731c155b36d45fd7dd1b16b756eb7cb27
1 file changed