Fix blockless multi usage

Author: byroot

lib/redis/client.rb

@@ -131,7 +131,7 @@ def call(command)
       reply = process([command]) { read }
       raise reply if reply.is_a?(CommandError)
 
-      if block_given?
+      if block_given? && reply != 'QUEUED'
         yield reply
       else
         reply

test/transactions_test.rb

@@ -10,6 +10,8 @@ def test_multi_discard
 
     assert_equal "QUEUED", r.set("foo", "1")
     assert_equal "QUEUED", r.get("foo")
+    assert_equal "QUEUED", r.zincrby("bar", 1,  "baz") # Floatify
+    assert_equal "QUEUED", r.hsetnx("plop", "foo", "bar") # Boolify
 
     r.discard