SET command family gives an error on empty body ('') in binary protocol

[bigbes]

No description provided.

[ligurio]

Reproduced on Tarantool 2.8.3-0-g01023dbc2 with patch:

--- a/test/binary/binary.test.py
+++ b/test/binary/binary.test.py
@@ -162,6 +162,11 @@ iequal(res[0]['val'], 9223372036854775809)
 res = mc.decr("bug21")
 iequal(res[0]['val'], 9223372036854775808)
 
+print("""#----------------------------------# bug 48 #---------------------------------#""")
+set("", 5, 19, "value")
+set("key", 5, 19, "")
+set("", 5, 19, "")
+
 print("""#-----------------------------------------------------------------------------#
 ################################ Diagnostics CAS ##############################
 #-----------------------------------------------------------------------------#""")