fix wrong length in snprintf

Summary: Closes https://github.com/facebook/rocksdb/pull/3622

Differential Revision: D7307689

Pulled By: ajkr

fbshipit-source-id: b8f52effc63fea06c2058b39c60944c2c1f814b4

db/db_compaction_filter_test.cc

@@ -109,7 +109,7 @@ class SkipEvenFilter : public CompactionFilter {
     int i = std::stoi(key.ToString());
     if (i / 10 % 2 == 0) {
       char key_str[100];
-      snprintf(key_str, sizeof(key), "%010d", i / 10 * 10 + 10);
+      snprintf(key_str, sizeof(key_str), "%010d", i / 10 * 10 + 10);
       *skip_until = key_str;
       ++cfilter_skips;
       return Decision::kRemoveAndSkipUntil;