handle vagrant internal change in 1.4.0

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
update using_nfs? check

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
fix to return host ip in any condition.

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
nfs: update action sequence

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
Merge pull request #126 from miurahr/fix_NFS_name_error

Fix nfs name error in Vagrant 1.4.0+