[net] Remove CombinerAll

This was introduced in 9519a9a for use with boost signals. Boost signals
have not been used in net since 8ad663c, so this code is unused

Author: jnewbery

src/net.h

@@ -595,21 +595,6 @@ void InterruptMapPort();
 void StopMapPort();
 uint16_t GetListenPort();
 
-struct CombinerAll
-{
-    typedef bool result_type;
-
-    template<typename I>
-    bool operator()(I first, I last) const
-    {
-        while (first != last) {
-            if (!(*first)) return false;
-            ++first;
-        }
-        return true;
-    }
-};
-
 /**
  * Interface for message handling
  */

src/test/validation_tests.cpp

@@ -9,7 +9,6 @@
 
 #include <test/util/setup_common.h>
 
-#include <boost/signals2/signal.hpp>
 #include <boost/test/unit_test.hpp>
 
 BOOST_FIXTURE_TEST_SUITE(validation_tests, TestingSetup)
@@ -120,20 +119,4 @@ BOOST_AUTO_TEST_CASE(signet_parse_tests)
     BOOST_CHECK(!CheckSignetBlockSolution(block, signet_params->GetConsensus()));
 }
 
-static bool ReturnFalse() { return false; }
-static bool ReturnTrue() { return true; }
-
-BOOST_AUTO_TEST_CASE(test_combiner_all)
-{
-    boost::signals2::signal<bool (), CombinerAll> Test;
-    BOOST_CHECK(Test());
-    Test.connect(&ReturnFalse);
-    BOOST_CHECK(!Test());
-    Test.connect(&ReturnTrue);
-    BOOST_CHECK(!Test());
-    Test.disconnect(&ReturnFalse);
-    BOOST_CHECK(Test());
-    Test.disconnect(&ReturnTrue);
-    BOOST_CHECK(Test());
-}
 BOOST_AUTO_TEST_SUITE_END()