Select factory image when --factory is given

prepare_test_image would prepare the correct image (test or factory)
but its return value would always specify the test image. This meant
that image_to_usb.sh would pick up the wrong image.

This commit fixes this.

BUG=chromium-os:12377
TEST=./image_to_usb --from=... --to=/dev/sdb
also with --factory
also with --test

Make sure it picks up the correct image in each case.

Change-Id: I165b604b448a6c938a47e57a667bd5f001626efe

Review URL: http://codereview.chromium.org/6609016

common.sh

@@ -645,7 +645,11 @@ prepare_test_image() {
     --image="$1/$2" --noinplace ${args}
 
   # From now on we use the just-created test image
-  CHROMEOS_RETURN_VAL="$1/${CHROMEOS_TEST_IMAGE_NAME}"
+  if [ ${FLAGS_factory} -eq ${FLAGS_TRUE} ]; then
+    CHROMEOS_RETURN_VAL="$1/${CHROMEOS_FACTORY_TEST_IMAGE_NAME}"
+  else
+    CHROMEOS_RETURN_VAL="$1/${CHROMEOS_TEST_IMAGE_NAME}"
+  fi
 }
 
 # Check that the specified file exists.  If the file path is empty or the file

mod_image_for_test.sh

@@ -178,8 +178,10 @@ IMAGE_DIR="$(dirname "${FLAGS_image}")"
 if [ ${FLAGS_inplace} -eq ${FLAGS_FALSE} ]; then
   if [ ${FLAGS_factory} -eq ${FLAGS_TRUE} ]; then
     TEST_PATHNAME="${IMAGE_DIR}/${CHROMEOS_FACTORY_TEST_IMAGE_NAME}"
+    typename="factory"
   else
     TEST_PATHNAME="${IMAGE_DIR}/${CHROMEOS_TEST_IMAGE_NAME}"
+    typename="test"
   fi
   if [ ! -f "${TEST_PATHNAME}" ] || \
      [ ${FLAGS_force_copy} -eq ${FLAGS_TRUE} ] ; then
@@ -188,7 +190,7 @@ if [ ${FLAGS_inplace} -eq ${FLAGS_FALSE} ]; then
       || die "Cannot copy ${FLAGS_image} to test image"
     FLAGS_image="${TEST_PATHNAME}"
   else
-    echo "Using cached test image"
+    echo "Using cached ${typename} image"
     exit
   fi