remove warning

Summary:
st_blocks shows 16 though the right value is 8. This happens occasionally which seems a bug.
Closes https://github.com/facebook/rocksdb/pull/2160

Differential Revision: D4893542

Pulled By: lightmark

fbshipit-source-id: 68e832586b58bbc6162efbe83ce273f1570d5be3

env/io_posix.cc

@@ -772,17 +772,9 @@ Status PosixWritableFile::Close() {
     fstat(fd_, &file_stats);
     // After ftruncate, we check whether ftruncate has the correct behavior.
     // If not, we should hack it with FALLOC_FL_PUNCH_HOLE
-    static bool buggy = false;
-    if (!buggy && (file_stats.st_size + file_stats.st_blksize - 1) /
+    if ((file_stats.st_size + file_stats.st_blksize - 1) /
             file_stats.st_blksize !=
         file_stats.st_blocks / (file_stats.st_blksize / 512)) {
-      fprintf(stderr,
-              "WARNING: Your kernel may be buggy (<= 4.0.x) and does not free "
-              "preallocated blocks on truncate. Hacking around it, but you "
-              "should upgrade!\n");
-      buggy = true;
-    }
-    if (buggy) {
       IOSTATS_TIMER_GUARD(allocate_nanos);
       if (allow_fallocate_) {
         fallocate(fd_, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, filesize_,