ts_conf: Fix unbounded write by scanf()

[szsam]

Buffer write operations that do not control the length of data written may overflow.

Also, the scanf format string "%[^\n]s" is ill-formed. It contains two independent format specifiers: "%[^\n]" followed by a lone "s". This will direct scanf to read everything until \n is encountered (leaving \n unread), and then require that the next input character is s. This just doesn't make any sense. No input will match such self-contradictory format. Reference: https://stackoverflow.com/questions/8177752/scanf-ns-a-vs-getsa