autotest: Ignore manifest-versions.

BUG=chromium:791888
TEST=manifest-versions is ignored.

Change-Id: I5eecf1aaa337804059ca755fd697e63ca0e6c63c
Reviewed-on: https://chromium-review.googlesource.com/888379
Commit-Ready: Shuhei Takahashi <[email protected]>
Tested-by: Shuhei Takahashi <[email protected]>
Reviewed-by: Mike Frysinger <[email protected]>
diff --git a/.gitignore b/.gitignore
index 9670263..ef18919 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,6 +50,7 @@
 monitor_db.pid
 server/cros/chaos_shadow_ap_list.conf
 server/site_tests/network_WiFiChaosPSK/control.local
+manifest-versions
 
 # These exist on the production servers.
 bug_filing_oauth_credentials.dat