Fix some lint warnings

db/version_edit.cc

@@ -31,7 +31,7 @@ enum Tag {
   // these are new formats divergent from open source leveldb
   kNewFile2             = 100,  // store smallest & largest seqno
 
-  kColumnFamily         = 200, // specify column family for version edit
+  kColumnFamily         = 200,  // specify column family for version edit
   kColumnFamilyAdd      = 201,
   kColumnFamilyDrop     = 202,
 };

db/version_edit.h

@@ -11,6 +11,7 @@
 #include <set>
 #include <utility>
 #include <vector>
+#include <string>
 #include "db/dbformat.h"
 
 namespace rocksdb {

db/version_set.cc

@@ -11,6 +11,7 @@
 
 #include <algorithm>
 #include <map>
+#include <set>
 #include <climits>
 #include <stdio.h>
 #include "db/filename.h"

db/write_batch.cc

@@ -92,7 +92,7 @@ Status WriteBatch::Iterate(Handler* handler) const {
   while (!input.empty() && handler->Continue()) {
     char tag = input[0];
     input.remove_prefix(1);
-    uint32_t column_family = 0; // default
+    uint32_t column_family = 0;  // default
     switch (tag) {
       case kTypeColumnFamilyValue:
         if (!GetVarint32(&input, &column_family)) {