Patch: https://review.openstack.org/#/c/352806 has
set host=None and we don't change this parameter
neither in devstack installation nor in manual installation.
With this patch value of [DEFAULT]/host is set to
hostname of the host on which magnum is setup.
Also, updated manual installation step to set [DEFAULT]/host
to hostname.
Depends-on: I51feb6ccdc0fab91a591568866e6801f2bbb319b
Change-Id: Id43bfcc792b28c98c9bf1d888dd7ddcc167e8ea5
Closes-Bug: #1630190
4ffad1d32d