Add ansible collections symlink to .gitignore
Add ansible collections symlink to .gitignore

https://review.opendev.org/#/c/742192/ added the creation of
symbolic link to Ansible Collections to env-setup.sh script
however it overlooked adding the symbolic link to .gitignore.
This change resolves this issue.

Change-Id: I5327b67d42b196c1e16d97ba562d1f7845ab407f

openstack/bifrost,openstack/bifrost