Fix tree Build issue

In jenkins pipeline of could see testing compilation happening However building tree is not complete, looking for an unknown file 15:53:04 Building HTML tree 15:53:05 error /yang/etsi-nfv.yang: [Errno 2] No such file or directory: '/yang/etsi-nfv.yang'

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information