Adds host_ip to hypervisor show API

After no-compute-fanout-to-scheduler, host_ip was stored in the table
of compute_nodes. Host ip address should be considered as the hypervisor
attribute similar to the hypervisor_type, hypervisor_version etc, and
now those attributes such as hypervisor_type, hypervisor_version etc
are all listed as the hypervisor attribute when calling "nova
hypervisor-show host", so we can also set "host_ip" as a new attribute
output for this command.

DocImpact
1) Only administrators can view hypervisor detail in nova.
2) It can help improve debug capabilities for nova. For example, if
admin using SimpleCIDRAffinityFilter, then after VM is deployed, admin
can check if the VM was deployed successfully to the desired host by
checking ip address of the host via "nova hypervisor-show host".
3) Add host_ip to the output for "nova hypervisor-show"

Implement bp hypervisor-show-ip
Change-Id: I006a504d030be1f47beb68a844647026a6daf0ce
Sync log.py from oslo

This change syncs log.py from oslo-incubator with commit
79e8a9a08daf563aa8a8d9280c9a6a27dcafc8f2

To honor RFC5424 add use_syslog_rfc_format config option
(default False, would be deprecated in J after existing
syslog format deprecation) which adds APP-NAME to syslog message
before MSG part to reflect application or service name.
Usable only with use_syslog, otherwise ignored.

During J, the default logging format for syslog should be changed
to always provide APP-NAME, thus use_syslog_rfc_format could be
deprecated in J as well.

Since the rootwrap code was graduating to a separate library,
so the rootwrap related change should just go into oslo.rootwrap
and when oslo.rootwrap is released, nova will pull in the library.

Change-Id: I6018c7322314a4b57052be1ec0fc5fa437069f44
Closes-bug: 904307
Merge "Sync log.py from oslo"
Merge "Adds host_ip to hypervisor show API"