lib.ec.ssh: Don't quote shell operators

Naively join()ing a command list to be executed remotely via SSH also
quotes shell operators which doesn't work, of course. Work around
that. The workaround will not always work but covers lots of cases.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/ec/ssh/AsyncSSH.py

@@ -6,6 +6,8 @@ from ...log import *
 from ...ExecContext import Result
 from ..SSHClient import SSHClient as Base
 
+from .util import join_cmd
+
 _USE_DEFAULT_KNOWN_HOSTS = object()
 
 class AsyncSSH(Base):
@@ -52,7 +54,7 @@ class AsyncSSH(Base):
         if not cmd:
             raise ValueError("cmd must not be empty")
 
-        inner = f"exec {shlex.join(cmd)}"
+        inner = f"exec {join_cmd(cmd)}"
         if wd is not None:
             inner = f"cd {shlex.quote(wd)} && {inner}"