Bring back the fix for COMMAND responses introduced in #273

[pje]

It seems the fix introduced by #273 was removed by #278.

This PR just brings back the fix introduced by #273—fixing the broken COMMAND response.

From #273:

When I use github.com/go-redis/redis/v8 redis.Command would return a error:

redis: can't parse array reply: "$9440"

The reason is that WriteBulk append $len(str) in front of the data. Correct response of Command should be $len(commands).

[pje]

There's an integration test for COMMAND, but it's skipped:

miniredis/integration/command_test.go

Lines 5 to 10 in 84b7146

	func TestCommand(t *testing.T) {
	t.Skip("not sure about this one yet")
	testRaw(t, func(c *client) {
	c.DoLoosely("COMMAND")
	})
	}

[alicebob]

Weird. Thanks for the fix!

[alicebob]

I missed that one. The inttest is a bit hard to get right, iirc.