mucmd: start process the same way as base process is started

       Fixes issue seen with rootless containers

munet/mucmd.py

@@ -90,19 +90,14 @@ def main(*args):
     ecmd = "/usr/bin/nsenter"
     eargs = [ecmd]
 
-    output = subprocess.check_output(["/usr/bin/nsenter", "--help"], encoding="utf-8")
-    if " -a," in output:
-        eargs.append("-a")
-    else:
-        # -U doesn't work
-        for flag in ["-u", "-i", "-m", "-n", "-C", "-T"]:
-            if f" {flag}," in output:
-                eargs.append(flag)
+    #start mucmd same way base process is started
+    eargs.append(f"--mount=/proc/{pid}/ns/mnt")
+    eargs.append(f"--net=/proc/{pid}/ns/net")
     eargs.append(f"--pid=/proc/{pid}/ns/pid_for_children")
+    eargs.append(f"--uts=/proc/{pid}/ns/uts")
     eargs.append(f"--wd={rundir}")
-    eargs.extend(["-t", pid])
     eargs += args.shellcmd
-    # print("Using ", eargs)
+    #print("Using ", eargs)
     return os.execvpe(ecmd, eargs, {**env, **envcfg})