build_image: Display progress bar message on stderr

Currently, progress bar messages are displayed on stdout through
echo. Move these messages to stderr so they are in the same
stream as the logging messages.

BUG=none
TEST=manual tests

Change-Id: Id20db4ecef51ddb1eb07ab13e83f8f43803c6410
Reviewed-on: https://chromium-review.googlesource.com/275726
Reviewed-by: David Pursell <dpursell@chromium.org>
Trybot-Ready: Ralph Nathan <ralphnathan@chromium.org>
Commit-Queue: Ralph Nathan <ralphnathan@chromium.org>
Tested-by: Ralph Nathan <ralphnathan@chromium.org>
diff --git a/build_image b/build_image
index 4a54366..db8e2ec 100755
--- a/build_image
+++ b/build_image
@@ -184,7 +184,7 @@
 mkdir -p "${BUILD_DIR}"
 
 if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-  echo 'operation: creating base image'
+  info 'operation: creating base image'
 fi
 
 # Create the base image.
@@ -192,7 +192,7 @@
   ${FLAGS_enable_bootcache}
 
 if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-  echo 'operation: done creating base image'
+  info 'operation: done creating base image'
 fi
 
 # Running board-specific setup if any exists.
@@ -201,7 +201,7 @@
 fi
 
 if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-  echo 'operation: creating developer image'
+  info 'operation: creating developer image'
 fi
 
 # Create a developer image if an image that is based on it is requested.
@@ -212,8 +212,8 @@
 fi
 
 if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-  echo 'operation: done creating developer image'
-  echo 'operation: creating test image'
+  info 'operation: done creating developer image'
+  info 'operation: creating test image'
 fi
 
 # From a developer image create a test|factory_test image.
@@ -228,7 +228,7 @@
 fi
 
 if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-  echo 'operation: done creating test image'
+  info 'operation: done creating test image'
 fi
 
 # Move the completed image to the output_root.
@@ -248,7 +248,7 @@
 summarize() {
 
   if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-    echo 'operation: summarize'
+    info 'operation: summarize'
   fi
 
   local name="$1" img="$2"
@@ -270,7 +270,7 @@
   echo
 
   if [[ ${FLAGS_progress_bar} -eq ${FLAGS_TRUE} ]]; then
-    echo 'operation: done summarize'
+    info 'operation: done summarize'
   fi
 }
 if should_build_image ${CHROMEOS_BASE_IMAGE_NAME}; then