Allow PRODUCT_PROPERTY_OVERRIDES to override default locale.

Change-Id: I5147d687750a50cfc186e99a9a8c88d3b2eb1692
If PRODUCT_PROPERTY_OVERRIDES has set default locale, buildinfo.sh skips setting them.
http://b/issue?id=2243115
diff --git a/tools/buildinfo.sh b/tools/buildinfo.sh
index 6c85149..ce3ee81 100755
--- a/tools/buildinfo.sh
+++ b/tools/buildinfo.sh
@@ -25,8 +25,12 @@
   echo "ro.product.cpu.abi2=$TARGET_CPU_ABI2"
 fi
 echo "ro.product.manufacturer=$PRODUCT_MANUFACTURER"
-echo "ro.product.locale.language=$PRODUCT_DEFAULT_LANGUAGE"
-echo "ro.product.locale.region=$PRODUCT_DEFAULT_REGION"
+if [ -n "$PRODUCT_DEFAULT_LANGUAGE" ] ; then
+  echo "ro.product.locale.language=$PRODUCT_DEFAULT_LANGUAGE"
+fi
+if [ -n "$PRODUCT_DEFAULT_REGION" ] ; then
+  echo "ro.product.locale.region=$PRODUCT_DEFAULT_REGION"
+fi
 echo "ro.wifi.channels=$PRODUCT_DEFAULT_WIFI_CHANNELS"
 echo "ro.board.platform=$TARGET_BOARD_PLATFORM"