bc: remove unnecessary NULL initializers

function                                             old     new   delta
zbc_program_assign                                   442     426     -16
zbc_program_exec                                    4043    3977     -66
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(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-82)             Total: -82 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed