googletest: Stop specifying Version in README.chromium.

//DEPS is the source of truth for the googletest version. This CL
follows the pattern in //third_party/skia, so googletest can be
auto-rolled using similar infrastructure.

Change-Id: Idd6597732174fad7ebd5b2eb69f78137749599bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1577970
Auto-Submit: Victor Costan <pwnall@chromium.org>
Commit-Queue: Staphany Park <staphany@chromium.org>
Reviewed-by: Staphany Park <staphany@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#652980}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 317de293a0b989503152db55a041df75244d1041
diff --git a/README.chromium b/README.chromium
index 9442881..3620274 100644
--- a/README.chromium
+++ b/README.chromium
@@ -1,7 +1,7 @@
 Name: Google Test: Google's C++ Testing Framework
 Short Name: googletest
 URL: https://github.com/google/googletest.git
-Version: 9f893b99598b1f0725dc8b92037f0d9f53095b90
+Version: unknown
 License: BSD
 License File: NOT_SHIPPED
 Security critical: no