Fix differing signedness

source/RobotAPI/libraries/armem/test/ArMemLTMBenchmark.cpp

@@ -100,7 +100,7 @@ BOOST_AUTO_TEST_CASE(test_memory_export__benchmark)
 
     TIMING_START(LTM_Export__Benchmark);
 
-    for (unsigned int i = 0; i < num_exports; ++i)
+    for (int i = 0; i < num_exports; ++i)
     {
         en.clear();
         auto& snap = en.addSnapshot(IceUtil::Time::now());