modify the gitignore to ignore vagrant related files

Change-Id: I637cc05859fb4dcbc1b7d1c5ebf22a0997b13137
diff --git a/.gitignore b/.gitignore
index d81967c..80e400d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,8 @@
 *.pyc
 *.project
 *.pydevproject
+
+# vagrant
+trellis/.vagrant/
+# virtualbox
+trellis/*.log