build-unit-test-docker: Update googletest

The current version of googletest has a memory use-after-free. This
was noticed when using ub+asan on sdeventplus. This patch updates
googletest to a newer version which contains a fix for the bug.

Newer googletest got rid of the need for -DBUILD_G{TEST,MOCK} cmake
flags.

Change-Id: Ib60d7522f3c238c7e2719b824eb1ffa46884f30a
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index 11cb6f5..6980705 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -91,8 +91,8 @@
   [boost]=1.68.0
   [cereal]=v1.2.2
   [CLI11]=v1.6.1
-  # Snapshot from 2018-10-11
-  [googletest]=b3b19a796cbb3222fb3a49daf3f0a9378e8505ad
+  # Snapshot from 2018-12-17
+  [googletest]=9ab640ce5e5120021c5972d7e60f258bfca64d71
   [json]=v3.3.0
   # libvncserver commit dd873fce451e4b7d7cc69056a62e107aae7c8e7a is required for obmc-ikvm
   # Snapshot from 2018-10-08
@@ -215,7 +215,7 @@
 cd googletest-* && \
 mkdir build && \
 cd build && \
-cmake ${CMAKE_FLAGS[@]} -DTHREADS_PREFER_PTHREAD_FLAG=ON -DBUILD_GTEST=ON -DBUILD_GMOCK=ON .. && \
+cmake ${CMAKE_FLAGS[@]} -DTHREADS_PREFER_PTHREAD_FLAG=ON .. && \
 make -j$(nproc) && \
 make install