Updates .gitignore with .checkstyle
Updates .gitignore with .checkstyle

Change-Id: Id4befba6e290e25ace943c1d8c10033ee1102cb8
Signed-off-by: Kanagaraj Manickam <d5e1a856e8c40aa2ff3675e5f1ef217f02f64c8d@huawei.com>

open-o/nfvo,open-o/nfvo,open-o/nfvo,open-o/nfvo,open-o/nfvo