Revert "Revert "Use --fast by default in build_image when --jobs is enabled.""

parallel_emerge prints a message every 30 seconds now so that buildbot doesn't
kill us early. Per discussion with cmasone, reverting the revert.

This reverts commit debaa3d8cf1cfcbcc77b2f44729f6e7f83625ca1.

build_image

@@ -92,6 +92,11 @@ if [ "${FLAGS_rootfs_size}" -gt "${FLAGS_rootfs_partition_size}" ] ; then
   exit 1
 fi
 
+if [ ${FLAGS_jobs} -ne -1 ]; then
+  EMERGE_JOBS="--jobs=${FLAGS_jobs}"
+  FLAGS_fast=${FLAGS_TRUE}
+fi
+
 EMERGE_BOARD_CMD="emerge-${FLAGS_board}"
 if [ "${FLAGS_fast}" -eq "${FLAGS_TRUE}" ]; then
   echo "Using alternate emerge"
@@ -161,10 +166,6 @@ if [[ ${FLAGS_factory_install} -eq ${FLAGS_TRUE} ]] ; then
   INSTALL_MASK="${INSTALL_MASK} ${FACTORY_INSTALL_MASK}"
 fi
 
-if [[ ${FLAGS_jobs} -ne -1 ]]; then
-  EMERGE_JOBS="--jobs=${FLAGS_jobs}"
-fi
-
 # Figure out ARCH from the given toolchain.
 # TODO: Move to common.sh as a function after scripts are switched over.
 TC_ARCH=$(echo "${CHOST}" | awk -F'-' '{ print $1 }')

common.sh

@@ -325,14 +325,13 @@ function die {
 }
 
 # Retry an emerge command according to $FLAGS_retries
-# The $EMERGE_JOBS flags will only be added the first time the command is run
 function eretry () {
+  $* && return 0
   local i=
   for i in $(seq $FLAGS_retries); do
     echo Retrying $*
-    $* $EMERGE_JOBS && return 0
-  done
     $* && return 0
+  done
   return 1
 }