Quick fix for a string format

Summary:

Fix one more string format issue that throws warning in mac

tools/sst_dump.cc

@@ -180,7 +180,9 @@ int main(int argc, char** argv) {
       output_hex = true;
     } else if (strcmp(argv[i], "--input_key_hex") == 0) {
       input_key_hex = true;
-    } else if (sscanf(argv[i], "--read_num=%ld%c", &n, &junk) == 1) {
+    } else if (sscanf(argv[i],
+               "--read_num=%lu%c",
+               (unsigned long*)&n, &junk) == 1) {
       read_num = n;
     } else if (strcmp(argv[i], "--verify_checksum") == 0) {
       verify_checksum = true;

util/histogram.cc

@@ -169,7 +169,7 @@ std::string HistogramImpl::ToString() const {
              // left
              (unsigned long)((b == 0) ? 0 : bucketMapper.BucketLimit(b-1)),
              (unsigned long)bucketMapper.BucketLimit(b), // right
-             buckets_[b],                 // count
+             (unsigned long)buckets_[b],                 // count
              (mult * buckets_[b]),        // percentage
              (mult * sum));               // cumulative percentage
     r.append(buf);