Function silc_hash_table_replace
SYNOPSIS
void silc_hash_table_replace(SilcHashTable ht, void *key, void *context);
DESCRIPTION
Same as silc_hash_table_add but if the `key' already exists in the
hash table the old key and the old context will be replaced with the
`key' and the `context. The destructor function will be called for the
replaced key and context.