MFC rev. 1.260
MFC rev. 1.260

Any call of tty_close() with a tty refcount of <= 1 is wrong and we will
free the tty in this case. This is a workaround until the underlaying
devfs/tty problems are fixed.

Approved by:	re

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase