Change <> to () for underflow op serial, avoids boost;:json escape.

Author: evoskuil

src/chain/operation.cpp

@@ -465,10 +465,10 @@ static std::string opcode_to_prefix(opcode code,
 std::string operation::to_string(uint32_t active_flags) const NOEXCEPT
 {
     if (!is_valid())
-        return "(?)";
+        return "?";
 
     if (underflow_)
-        return "<" + encode_base16(get_data()) + ">";
+        return "(" + encode_base16(get_data()) + ")";
 
     if (data_empty())
         return opcode_to_mnemonic(code_, active_flags);

test/chain/operation.cpp

@@ -781,7 +781,7 @@ BOOST_AUTO_TEST_CASE(operation__to_string__empty_underflow__empty)
     operation value(encoded);
     BOOST_REQUIRE(value.is_invalid());
     BOOST_REQUIRE(value.is_underflow());
-    BOOST_REQUIRE_EQUAL(value.to_string(0), "<>");
+    BOOST_REQUIRE_EQUAL(value.to_string(0), "()");
 }
 
 BOOST_AUTO_TEST_CASE(operation__to_string__non_empty_underflow__empty)
@@ -791,7 +791,7 @@ BOOST_AUTO_TEST_CASE(operation__to_string__non_empty_underflow__empty)
     operation value(encoded);
     BOOST_REQUIRE(value.is_invalid());
     BOOST_REQUIRE(value.is_underflow());
-    BOOST_REQUIRE_EQUAL(value.to_string(0), "<02ff>");
+    BOOST_REQUIRE_EQUAL(value.to_string(0), "(02ff)");
 }
 
 BOOST_AUTO_TEST_CASE(operation__to_string__nop2_no_rules__nop2)