update list of files for git to ignore

These files are all created in the course of running
devstack and openstack but should not be tracked
as part of the devstack sources.

Change-Id: Ia3939c6e20f8d6fadaa18d2f3619361dc9375696
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>
diff --git a/.gitignore b/.gitignore
index 83c5419..c5744b3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,10 @@
 *~
 .*.sw[nop]
 *.log
+*.log.[1-9]
 src
 localrc
 local.sh
+files/*.gz
+files/images
+stack-screenrc