Add Build Timer

build_image

Index: build_image
diff --git a/build_image b/build_image
index 2fad0fed0068fcc5da4262e71cc6d2dc3520f124..34d2b62f410a7616c70482673059c9af1c880741 100755
--- a/build_image
+++ b/build_image
@@ -138,9 +138,6 @@ if [[ -e "$OUTPUT_DIR" ]]; then
   fi
 fi
 
-# Be verbose to help debug failures.
-set -x
-
 # Create the output directory.
 mkdir -p "$OUTPUT_DIR"
 
@@ -567,6 +564,9 @@ fi
 if [ "$FLAGS_withdev" -eq "$FLAGS_TRUE" ]; then
   echo "Developer image created as $DEVELOPER_IMAGE_NAME"
 fi
+
+print_time_elapsed
+
 echo "To copy to USB keyfob, OUTSIDE the chroot, do something like:"
 echo "  ./image_to_usb.sh --from=${OUTSIDE_OUTPUT_DIR} --to=/dev/sdX"
 echo "To convert to VMWare image, OUTSIDE the chroot, do something like:"