cache: Remove unused return from 'cache_key_exist'

If 'tmp' isn't accessed, 0 is returned by the function anyway. This
is a duplicate case therefore is not needed.

Signed-off-by: RJ Trujillo <certifiedblyndguy@gmail.com>

src/cache.c

@@ -243,8 +243,6 @@ cache_key_exist(struct cache *cache, char *key, size_t key_len)
         tmp->ts = ev_time();
         HASH_ADD_KEYPTR(hh, cache->entries, tmp->key, key_len, tmp);
         return 1;
-    } else {
-        return 0;
     }
 
     return 0;