cleanup: move init funcs to the top of the source

We make sure they're not hiding at the bottom or in the middle
which makes debugging an utter nightmare!

Signed-off-by: Milos Gajdos <milosthegajdos@gmail.com>

registry/proxy/proxyblobstore_test.go

@@ -20,14 +20,20 @@ import (
 	"github.com/opencontainers/go-digest"
 )
 
-var sbsMu sync.Mutex
-var randSource rand.Rand
+var (
+	sbsMu      sync.Mutex
+	randSource rand.Rand
+)
 
 type statsBlobStore struct {
 	stats map[string]int
 	blobs distribution.BlobStore
 }
 
+func init() {
+	randSource = *rand.New(rand.NewSource(42))
+}
+
 func (sbs statsBlobStore) Put(ctx context.Context, mediaType string, p []byte) (distribution.Descriptor, error) {
 	sbsMu.Lock()
 	sbs.stats["put"]++
@@ -195,10 +201,6 @@ func makeBlob(size int) []byte {
 	return blob
 }
 
-func init() {
-	randSource = *rand.New(rand.NewSource(42))
-}
-
 func populate(t *testing.T, te *testEnv, blobCount, size, numUnique int) {
 	var inRemote []distribution.Descriptor