race fix: pinner loads with a threadsafe datastore

All the datastores used by pinners and so on should be mutex
wrapped. One issue with changing all of them from
ds.Datastore -> ds.ThreadSafeDatastore is that we wrap the
incoming ds.ThreadSafeDatastore with other datastores, which
do not implement the interface. Re-wrapping again causes
double locking. (which may be ok..., but...) any ideas?

pin.go

@@ -53,11 +53,11 @@ type pinner struct {
 	directPin  set.BlockSet
 	indirPin   *indirectPin
 	dserv      mdag.DAGService
-	dstore     ds.Datastore
+	dstore     ds.ThreadSafeDatastore
 }
 
 // NewPinner creates a new pinner using the given datastore as a backend
-func NewPinner(dstore ds.Datastore, serv mdag.DAGService) Pinner {
+func NewPinner(dstore ds.ThreadSafeDatastore, serv mdag.DAGService) Pinner {
 
 	// Load set from given datastore...
 	rcds := nsds.Wrap(dstore, recursePinDatastoreKey)
@@ -176,7 +176,7 @@ func (p *pinner) IsPinned(key util.Key) bool {
 }
 
 // LoadPinner loads a pinner and its keysets from the given datastore
-func LoadPinner(d ds.Datastore, dserv mdag.DAGService) (Pinner, error) {
+func LoadPinner(d ds.ThreadSafeDatastore, dserv mdag.DAGService) (Pinner, error) {
 	p := new(pinner)
 
 	{ // load recursive set

pin_test.go

@@ -21,8 +21,8 @@ func randNode() (*mdag.Node, util.Key) {
 }
 
 func TestPinnerBasic(t *testing.T) {
-	dstore := ds.NewMapDatastore()
-	bstore := blockstore.NewBlockstore(dssync.MutexWrap(dstore))
+	dstore := dssync.MutexWrap(ds.NewMapDatastore())
+	bstore := blockstore.NewBlockstore(dstore)
 	bserv, err := bs.New(bstore, offline.Exchange(bstore))
 	if err != nil {
 		t.Fatal(err)