Fix wrong nscp path w/ command_endpoint runtime macros

Fix wrong nscp path w/ command_endpoint runtime macros

Do not allow to override the nscp path by runtime macros.
This causes the (linux) master to send just "." as $nscp_path$
and the windows client ignores the local global constant NscpPath
being overridden by the master.

Only happens with command_endpoints where runtime macros are passed
from the master to the clients.

fixes #9456