Fix corruption with multiple emacsclient -t instances.

Fix corruption with multiple emacsclient -t instances.

This bug was introduced by my 2013-08-26 patch, which incorrectly
assumed that the terminfo implementation doesn't use termcap buffers.
* term.c (init_tty) [TERMINFO]: Remove optimization, as
these buffers apparently are used after all.
* termchar.h (TERMCAP_BUFFER_SIZE) [TERMINFO]: Define here too.
(struct tty_display_info): Define members termcap_term_buffer and
termcap_strings_buffer even if TERMINFO.

Fixes: debbugs:15222