free(NULL) is a valid NOP. Most of the hiredis free functions behave the
same way. redisReaderFree is updated to also be NULL-safe.
There is one redundant NULL check at sds.c:1036, but it's left as is
since sds is imported from upstream.
Signed-off-by: Justin Brewer <jzb0012@auburn.edu>
calloc is guaranteed to provide a zero-initialized buffer. There is
no need to set fields to zero explicitly.
Signed-off-by: Justin Brewer <jzb0012@auburn.edu>
