1.Since the local.conf need to live on devstack directory
Refine the cat command to be obvious
2.Also fix one issue, as devstack would use localrc directly
if localrc file exists, but localrc not have enable_plugin
setting. This would cause devstack install without magnum enable.
So we use local.conf as the default configuration kick point to
make magnum can be installed with devstack
Closes-Bug: #1441977
Change-Id: Ib06cd38ed9744d42e664ff92d486c29e7932851f
5114844325