Back out "Add warning on adding nbits to LSH index factory" (#3690)

Summary:
Pull Request resolved: #3690

Seems like this may not be necessary because it is the the expected behavior.

See: #3687 (comment)

Reviewed By: asadoughi

Differential Revision: D60241747

fbshipit-source-id: 7b8780fc4922a58c1975ae1b4343dc87e0eda0e1

faiss/index_factory.cpp

@@ -531,15 +531,7 @@ Index* parse_other_indexes(
 
     // IndexLSH
     if (match("LSH([0-9]*)(r?)(t?)")) {
-        int nbits;
-        if (sm[1].length() > 0) {
-            nbits = std::stoi(sm[1].str());
-        } else {
-            nbits = d;
-            fprintf(stderr,
-                    "WARN: nbits not specified, defaulting to d = %d\n",
-                    d);
-        }
+        int nbits = sm[1].length() > 0 ? std::stoi(sm[1].str()) : d;
         bool rotate_data = sm[2].length() > 0;
         bool train_thresholds = sm[3].length() > 0;
         FAISS_THROW_IF_NOT(metric == METRIC_L2);