disable p2p in unit tests

The change replaces previous measure against unit tests "talking with outside world" as that
way would sometimes cause problems with debugging (especially concurrent debugging of two
versions was not possible).

libraries/plugins/chain/chain_plugin.cpp

@@ -1351,4 +1351,9 @@ bool chain_plugin::is_p2p_enabled() const
   return my->is_p2p_enabled;
 }
 
+void chain_plugin::disable_p2p() const
+{
+  my->is_p2p_enabled = false;
+}
+
 } } } // namespace hive::plugis::chain::chain_apis

libraries/plugins/chain/include/hive/plugins/chain/chain_plugin.hpp

@@ -132,6 +132,7 @@ class chain_plugin : public plugin< chain_plugin >
   synchronization_type on_sync;
 
   bool is_p2p_enabled() const;
+  void disable_p2p() const;
 
 private:
   std::unique_ptr< detail::chain_plugin_impl, detail::chain_plugin_impl_deleter > my;

libraries/plugins/witness/witness_plugin.cpp

@@ -584,7 +584,7 @@ void witness_plugin::plugin_startup()
 
   if( !my->_is_p2p_enabled )
   {
-    ilog("Witness plugin is not enabled, beause P2P plugin is disabled...");
+    ilog("Witness plugin is not enabled, because P2P plugin is disabled...");
     return;
   }
 

tests/unit/db_fixture/hived_fixture.cpp

@@ -56,11 +56,7 @@ void hived_fixture::postponed_init_impl( const config_arg_override_t& config_arg
       // Register every plugin existing in repository as hived does.
       hive::plugins::register_plugins();
 
-      // We don't want p2p plugin connections at all.
-      config_arg_override_t default_overrides = {
-        config_line_t( { "p2p-endpoint", { "127.0.0.1:2345" } } ),
-        config_line_t( { "p2p-seed-node",{ " " } } )
-      };
+      config_arg_override_t default_overrides = {};
 
       if( not config_arg_overrides.empty() )
         std::copy_if( config_arg_overrides.begin(),
@@ -113,7 +109,9 @@ void hived_fixture::postponed_init_impl( const config_arg_override_t& config_arg
       BOOST_REQUIRE( db_plugin );
       db_plugin->logging = false;
 
-      db = &app.get_plugin< hive::plugins::chain::chain_plugin >().db();
+      auto& chain = app.get_plugin< hive::plugins::chain::chain_plugin >();
+      chain.disable_p2p(); // We don't want p2p plugin connections at all.
+      db = &chain.db();
       BOOST_REQUIRE( db );
       db->_log_hardforks = false;