Fixes a resource leak in gtest-port_test (by Haruka Iwao).

git-svn-id: http://googletest.googlecode.com/svn/trunk@587 861a406c-534a-0410-8894-cb66d6ee9925

Author: vladlosev

test/gtest-port_test.cc

@@ -1037,6 +1037,7 @@ class AtomicCounterWithMutex {
       SleepMilliseconds(random_.Generate(30));
 
       GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_unlock(&memory_barrier_mutex));
+      GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_destroy(&memory_barrier_mutex));
     }
     value_ = temp + 1;
   }