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
Fix the indents of v3 API sample docs

There are some indent typos in v3 API sample docs.
Most API samples' indents are 4 spaces, but some samples' indents
are 2 spaces. This patch fixes them.

These typos have been found during the work for auto-generating API
API sample docs from API validation schemas. The auto-generator'll
output API sample docs with json.dumps() method and that would make
the difference between current docs which are fixed with this patch
because the generator would make API samples consistent.
This patch's purpose is also for preparing the generator.

Change-Id: Ieb6e587fcf4c01c128199950db93e1087bc43f41
Merge "Adds host_ip to hypervisor show API"
Merge "Fix the indents of v3 API sample docs"