Print datestamp before doing anything

This lets easily see if Travis' "restart build" feature is working properly

tests/ci/receiver

@@ -5,6 +5,7 @@ export PATH=/usr/local/sbin:/usr/sbin:/sbin:/bin:/usr/bin:/usr/local/bin
 unset GIT_DIR
 
 if [[ $2 == *dokku* ]]; then
+  date -uIseconds
   rm -rf /tmp/build
   mkdir /tmp/build
   cd /tmp/build
@@ -33,4 +34,4 @@ if [[ $2 == *dokku* ]]; then
   done
 else
   echo "-----> Repository invalid."
-fi
+fi