Remove comments mentioning borrowing code from redis repository.

This is no longer true. Files slog.[ch] were introduced in webdis codebase by
mrb <michaelrbernstein@gmail.com> and were merged into master branch by
upstream developer in commit bec19d06. This file originally contained one
function void slog(...) with 13 statements. 12 of these statements were copied
from function void redisLog(...) from redis-server codebase
(https://github.com/antirez/redis, commit aa81e4d5, file src/redis.c, 18
statements). Since that time these files were refactored and have nothing to do
with the codebase it was originally based on. Not to mention current
src/redis.c from redis repository greatly differs from the mentioned commit
where code was borrowed from.

slog.c

@@ -1,4 +1,3 @@
-/* A slog is a simple log. Basically extracted from antirez/redis. */
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>