f_vty_transceive: allow to ignore unknown vty commands

When a new test uses a VTY configuration that may not yet be available in the
'latest' build, it can be useful to ignore the "Unknown VTY Command" error.

To be used by f_init() for multiple MSCs, setting a default 'allow-attach' flag
per MSC implicitly -- such vty config is not yet supported in the latest build.

Change-Id: I284c42e10c0cb282c8410db87959b471867edef6
1 file changed