[S-mailx] inappropriate errors NAIL_NO_SYSTEM_RC and NAIL_EXTRA_RC

[russellbell]

        I switched to packaged s-nailx today s-nail-14.9.16 and get
these warnings:

        mailx: Warning: variable superseded or obsoleted: NAIL_NO_SYSTEM_RC
        mailx: Warning: variable superseded or obsoleted: NAIL_EXTRA_RC

I don't set these variables anywhere.

russell bell