Updates .gitignore
Updates .gitignore

To ignore swap files from getting into repository
currently the implemented ignore is *.swp
however vim adds more swap files if these files exists,
so improving this with *.sw?

Change-Id: I03cae7b9b0c2a8bef30e5f4b39c0d75e752d7f6b
Closes-Bug: #1255884

rdo-management/tripleo-image-elements,radez/tripleo-image-elements,openstack/tripleo-image-elements,rdo-management/tripleo-image-elements,openstack/tripleo-image-elements,radez/tripleo-image-elements