Update copyright in libssp.

libssp/ChangeLog

libssp/Makefile.am

libssp/gets-chk.c

libssp/memcpy-chk.c

libssp/memmove-chk.c

libssp/mempcpy-chk.c

libssp/memset-chk.c

libssp/snprintf-chk.c

libssp/sprintf-chk.c

libssp/ssp-local.c

libssp/ssp.c

libssp/ssp/ssp.h.in

libssp/ssp/stdio.h

libssp/ssp/string.h

libssp/ssp/unistd.h

libssp/stpcpy-chk.c

libssp/strcat-chk.c

libssp/strcpy-chk.c

libssp/strncat-chk.c

libssp/strncpy-chk.c