THRIFT-4106: fix errors concurrency_test was identifying
Client: C++

This closes #1343
diff --git a/appveyor.yml b/appveyor.yml
index fc09f87..4c2e364 100755
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -40,7 +40,7 @@
      LIBEVENT_VERSION: 2.0.22
      QT_VERSION: 5.6
      ZLIB_VERSION: 1.2.8
-     DISABLED_TESTS: StressTestNonBlocking|concurrency_test
+     DISABLED_TESTS: StressTestNonBlocking
 
    - PROFILE: MSVC2015
      PLATFORM: x64