Update pin of third_party/glog b6a5e05 -> 59130c4

This is to pick up
https://fuchsia-review.googlesource.com/?polygerrit=0#/c/third_party/glog/+/145652/

Also, when passing the path of the the gflags install dir to
the glog build, use |cobalt_gflags_DIR| as the variable name
instead of |gflags_dir|. The latter variable name seemed to
already be used somehow by the glog build for a different purpose
so specifying a name that includes the string "cobalt".

Change-Id: I7abffdae1a2a69608b88f54bba0ca1d7fa1d7c9f
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1bacf72..2ae7ee7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -109,7 +109,7 @@
                     CMAKE_ARGS  -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                                 -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
                                 -DCMAKE_CXX_FLAGS=${EXTERNAL_PROJECT_CMAKE_CXX_FLAGS}
-                                -Dgflags_DIR=${GFLAGS_INSTALL_DIR}
+                                -Dcobalt_gflags_DIR=${GFLAGS_INSTALL_DIR}
                                 -DCMAKE_INSTALL_PREFIX:PATH=${GLOG_INSTALL_DIR}
                     DEPENDS     gflags_external_project
                    )
diff --git a/third_party/glog b/third_party/glog
index b6a5e05..59130c4 160000
--- a/third_party/glog
+++ b/third_party/glog
@@ -1 +1 @@
-Subproject commit b6a5e0524c28178985f0d228e9eaa43808dbec3c
+Subproject commit 59130c4dbcefcbcfa23bbadaedd846862879a620