Update reference to gtest thirdparty module.

Zhang Ye · Zhang Ye · commit 47d73200966b · 2016-06-08T09:36:03.000+08:00
diff --git a/.gitmodules b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "thirdparty/gtest"]
 	path = thirdparty/gtest
-	url = https://chromium.googlesource.com/external/googletest.git
+	url = https://github.com/google/googletest.git
diff --git a/thirdparty/gtest b/thirdparty/gtest
@@ -1 +1 @@
-Subproject commit 0476e154db5fab1721c2a0f32abf4aa773679b52
+Subproject commit 0a439623f75c029912728d80cb7f1b8b48739ca4
