fs: return blksize on stats object

Oversight to not pass blksize to fs.Stats on initialization.

Also added a test to make sure the object property has been set. Since
now on Windows both blksize and blocks will simply be set to undefined.

lib/fs.js

@@ -125,6 +125,7 @@ fs.Stats = function(
     uid,
     gid,
     rdev,
+    blksize,
     ino,
     size,
     blocks,
@@ -138,6 +139,7 @@ fs.Stats = function(
   this.uid = uid;
   this.gid = gid;
   this.rdev = rdev;
+  this.blksize = blksize;
   this.ino = ino;
   this.size = size;
   this.blocks = blocks;

src/node_file.cc

@@ -400,6 +400,7 @@ Local<Value> BuildStatsObject(Environment* env, const uv_stat_t* s) {
     uid,
     gid,
     rdev,
+    blksize,
     ino,
     size,
     blocks,

test/simple/test-fs-stat.js

@@ -36,6 +36,11 @@ fs.stat('.', function(err, stats) {
   assert(this === global);
 });
 
+fs.stat('.', function(err, stats) {
+  assert.ok(stats.hasOwnProperty('blksize'));
+  assert.ok(stats.hasOwnProperty('blocks'));
+});
+
 fs.lstat('.', function(err, stats) {
   if (err) {
     got_error = true;