Update //third_party/protobuf to version 3.

third_party/protobuf/cmake/protobuf-config.cmake.in

Index: third_party/protobuf/cmake/protobuf-config.cmake.in
diff --git a/third_party/protobuf/cmake/protobuf-config.cmake.in b/third_party/protobuf/cmake/protobuf-config.cmake.in
new file mode 100644
index 0000000000000000000000000000000000000000..bb0997b88be7edc6c623af1a29128695ba5e0d43
--- /dev/null
+++ b/third_party/protobuf/cmake/protobuf-config.cmake.in
@@ -0,0 +1,27 @@
+# Version info variables
+set(PROTOBUF_VERSION        "@protobuf_VERSION@")
+set(PROTOBUF_VERSION_STRING "@protobuf_VERSION_STRING@")
+
+# Current dir
+get_filename_component(_PROTOBUF_PACKAGE_PREFIX
+  "${CMAKE_CURRENT_LIST_FILE}" PATH)
+
+# Imported targets
+include("${_PROTOBUF_PACKAGE_PREFIX}/protobuf-targets.cmake")
+
+# Compute the installation prefix relative to this file.
+get_filename_component(_PROTOBUF_IMPORT_PREFIX
+  "${_PROTOBUF_PACKAGE_PREFIX}" PATH)
+get_filename_component(_PROTOBUF_IMPORT_PREFIX
+  "${_PROTOBUF_IMPORT_PREFIX}" PATH)
+get_filename_component(_PROTOBUF_IMPORT_PREFIX
+  "${_PROTOBUF_IMPORT_PREFIX}" PATH)
+
+# CMake FindProtobuf module compatible file
+if(NOT DEFINED PROTOBUF_MODULE_COMPATIBLE OR "${PROTOBUF_MODULE_COMPATIBLE}")
+  include("${_PROTOBUF_PACKAGE_PREFIX}/protobuf-module.cmake")
+endif()
+
+# Cleanup temporary variables.
+set(_PROTOBUF_PACKAGE_PREFIX)
+set(_PROTOBUF_IMPORT_PREFIX)