Fix LITE mode build failure

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5588

Test Plan: make LITE=1 all check

Differential Revision: D16354543

Pulled By: anand1976

fbshipit-source-id: 327a171439e183ac3a5e5057c511d6bca445e97d

db/import_column_family_test.cc

@@ -555,7 +555,7 @@ int main(int argc, char** argv) {
 #else
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
   fprintf(stderr,
           "SKIPPED as External SST File Writer and Import are not supported "
           "in ROCKSDB_LITE\n");