Fix send_args for EvmDatabaseOps.restore

The `send_args` that are to be passed to `MiqFileStorage.download`
didn't account for the changes between `.upload` and `.download`, which
downloading expects a `nil` for the first argument when in block form
(who writes this crap*...).

To account for that, we prepend the `nil` value if we are doing a
`.restore`, which is the only time we are doing a download from a file
storage.

Partially addresses issues in the following tickets:

  - https://bugzilla.redhat.com/show_bug.cgi?id=1633573
  - https://bugzilla.redhat.com/show_bug.cgi?id=1513520

* Hint:  It was me...

lib/evm_database_ops.rb

@@ -136,6 +136,13 @@ def self.restore(db_opts, connect_opts = {})
     MiqFileStorage.with_interface_class(connect_opts) do |file_storage|
       send_args = [uri, db_opts[:byte_count]].compact
 
+      # Okay, this probably seems a bit silly seeing that we just went to the
+      # trouble of doing a `.compact)`.  The intent is that with a restore, we
+      # are doing a `MiqFileStorage.download`, and the interface for that
+      # method is to pass a `nil` for the block form since we are streaming the
+      # data from the command that we are writting as part of the block.
+      send_args.unshift(nil) if action == :restore
+
       # Note:  `input_path` will always be a fifo stream (input coming from
       # PostgresAdmin, and the output going to the `uri`), since we want to
       # maintain the same interface for all backup types.

spec/lib/evm_database_ops_spec.rb

@@ -287,7 +287,7 @@ def execute_with_file_storage(action = :backup)
 
       context "for a restore action" do
         it "updates db_opts[:local_file] in the method context" do
-          expect(file_storage).to receive(:send).with(:download, "smb://tmp/foo")
+          expect(file_storage).to receive(:send).with(:download, nil, "smb://tmp/foo")
           execute_with_file_storage(:restore)
         end