Unlink file temp file immediately

In case the download is terminated, it's best to have unlinked the file
to avoid large files lingering. Since we're passing in an IO buffer
instead of a path, We need to seek to the beginning of the file in order
to read from it.

lib/fog/storage/google_json/requests/get_object.rb

@@ -39,6 +39,7 @@ def get_object(bucket_name, object_name,
           raise ArgumentError.new("object_name is required") unless object_name
 
           buf = Tempfile.new("fog-google-storage-temp")
+          buf.unlink
 
           # Two requests are necessary, first for metadata, then for content.
           # google-api-ruby-client doesn't allow fetching both metadata and content
@@ -57,14 +58,15 @@ def get_object(bucket_name, object_name,
           @storage_json.get_object(
             bucket_name,
             object_name,
-            **all_opts.merge(:download_dest => buf.path)
+            **all_opts.merge(:download_dest => buf)
           )
 
+          buf.seek(0)
+
           if block_given?
             yield buf.read, nil, nil
           else
             object[:body] = buf.read
-            buf.unlink
           end
 
           object