test: rename bench_func to remote_echo

The function simply returns passed arguments, just like echo. Let's
call it with more convenient name that doesn't have anything in common
with benchmarks to use it in tests later.

Part of #108

Author: drewdzzz

test/ClientPerfTest.cpp

@@ -100,7 +100,7 @@ executeRequest(Connection<BUFFER, NetProvider> &conn, int request_type, int key)
 		case Iproto::SELECT:
 			return conn.space[space_id].select(std::make_tuple(key));
 		case Iproto::CALL:
-			return conn.call("bench_func", std::make_tuple(1, 2, 3, 4, 5));
+			return conn.call("remote_echo", std::make_tuple(1, 2, 3, 4, 5));
 		default:
 			abort();
 	}

test/cfg.lua

@@ -30,7 +30,7 @@ function remote_map()
     return {key = 777}
 end
 
-function bench_func(...)
+function remote_echo(...)
     return {...}
 end
 

test/cfg_ssl.lua

@@ -28,7 +28,7 @@ function remote_multi()
     return 'Hello', 1, 6.66
 end
 
-function bench_func(...)
+function remote_echo(...)
     return {...}
 end