hush shell: Avoid string write overflow when entering max cmd length

console_buffer array is defined to be CONFIG_SYS_CBSIZE + 1 long,
whereas the_command array only CONFIG_SYS_CBSIZE long. Subsequent
use of strcpy(the_command, console_buffer) will write final \0
terminating byte outside the_command array when entering a command
of max length.

Signed-off-by: Kristian Otnes <kotnes <at> cisco <dot> com>