git_auto_update: Fixed default reload_command to "true"

An empty default value would result in an error thrown.

roles/git_auto_update/templates/update.sh

@@ -24,7 +24,7 @@ if [ -z "$GPG_FINGERPRINT" ] || (git verify-tag --raw "$TAG" 2>&1 | grep " VALID
   git reset --hard;
   git checkout -q "$TAG";
   chown -R "$DEST_USER:$DEST_GROUP" .;
-  if ! sh -c {{ reload_command | default('') | quote }}; then
+  if ! sh -c {{ reload_command | default('true') | quote }}; then
     echo "Failed during reload" >&2;
     exit 2;
   fi