host: remove preexec_fn from process run

According to documentation, to use setsid() before process.Popen via
preexec_fn is a bad practice. The documentation suggests to use the
start_new_session=True parameter in order to start a new session with a
new group ID.

Reference:
https://docs.python.org/3/library/subprocess.html#popen-constructor

Signed-off-by: Andrea Cervesato <[email protected]>

libkirk/host.py

@@ -146,7 +146,7 @@ async def run_command(
                 "stdout": asyncio.subprocess.PIPE,
                 "stderr": asyncio.subprocess.STDOUT,
                 "cwd": cwd,
-                "preexec_fn": os.setsid
+                "start_new_session": True
             }
 
             if env: