Add support for GlacierBlobStore.getBlobAccess

It is currently throwing UnsupportedOperationException exception.

glacier/src/main/java/org/jclouds/glacier/blobstore/GlacierBlobStore.java

@@ -364,7 +364,7 @@ public void removeBlob(String container, String key) {
 
    @Override
    public BlobAccess getBlobAccess(String container, String name) {
-      throw new UnsupportedOperationException("not implemented");
+      return BlobAccess.PRIVATE;
    }
 
    @Override