Add missing gflags and glog logging includes.

Change-Id: I382af4894c5369fe33d78fdf0e8d9cf5435eeda8

examples/more_garbow_hillstrom.cc

diff --git a/examples/more_garbow_hillstrom.cc b/examples/more_garbow_hillstrom.cc
index 03ecb9a..5e4d6e1 100644
--- a/examples/more_garbow_hillstrom.cc
+++ b/examples/more_garbow_hillstrom.cc
@@ -54,6 +54,8 @@
 #include <cmath>
 #include <iostream>
 #include "ceres/ceres.h"
+#include "gflags/gflags.h"
+#include "glog/logging.h"
 
 namespace ceres {
 namespace examples {