run_cmd: do not emit stderr to console

During repo-root probing errors are expected. However, these are emitted
to the caller terminal as we do not internally redirect them. We now
also caputure stderr on run_cmd.

Sample output:
  2024-12-11 09:59:34 - INFO     - kas 4.6 started
  fatal: not a git repository (or any parent up to mount point /)
  Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
  abort: no repository found in '/work' (.hg not found)
  fatal: not a git repository (or any parent up to mount point /)
  Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
  abort: no repository found in '/work' (.hg not found)
  2024-12-11 09:59:34 - INFO     - Using /repo as root for repository cip-core

Fixes: bbbc087 ("fix(run_cmd): handle not-executable errors")
Signed-off-by: Felix Moessbauer <[email protected]>

kas/libkas.py

@@ -186,7 +186,7 @@ def run_cmd(cmd, cwd, env=None, fail=True):
     logging.debug('%s$ %s', cwd, cmdstr)
 
     try:
-        ret = subprocess_run(cmd, env=env, cwd=cwd, stdout=PIPE)
+        ret = subprocess_run(cmd, env=env, cwd=cwd, stdout=PIPE, stderr=PIPE)
         if ret.returncode and fail:
             raise CommandExecError(cmd, ret.returncode)
     except FileNotFoundError as ex: