Fix unit test which breaks lite build

Summary: Comment out assertion of number of table files from lite build.

Test Plan:
    OPT=-DROCKSDB_LITE make check

Reviewers: lightmark

Reviewed By: lightmark

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60999

db/db_flush_test.cc

@@ -42,8 +42,9 @@ TEST_F(DBFlushTest, FlushWhileWritingManifest) {
   ASSERT_OK(dbfull()->Flush(no_wait));
   // If the issue is hit we will wait here forever.
   dbfull()->TEST_WaitForFlushMemTable();
-
+#ifndef ROCKSDB_LITE
   ASSERT_EQ(2, TotalTableFiles());
+#endif  // ROCKSDB_LITE
 }
 
 }  // namespace rocksdb