otautil: Export headers.

Test: mmma bootable/recovery
Change-Id: Ic01b68e2a394d578fc9fc09da2dabe9061b98122
diff --git a/otautil/ThermalUtil.cpp b/otautil/ThermalUtil.cpp
index 13d3643..5d9bd45 100644
--- a/otautil/ThermalUtil.cpp
+++ b/otautil/ThermalUtil.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "ThermalUtil.h"
+#include "otautil/ThermalUtil.h"
 
 #include <dirent.h>
 #include <stdio.h>
@@ -77,4 +77,4 @@
   }
   LOG(INFO) << "current maximum temperature: " << max_temperature;
   return max_temperature;
-}
\ No newline at end of file
+}