VMware: update the default 'task_poll_interval' time

The original means that each operation against the backend takes at
least 5 seconds. The default is updated to 0.5 seconds.

DocImpact
    Updated default value for task_poll_interval from 5 seconds to
    0.5 seconds

Change-Id: I867b913f52b67fa9d655f58a2e316b8fd1624426
Closes-bug: #1274439
Fix a couple of unit test typos

There were two cases in rpcapi unit tests where it was checking method instead
of rpc_method.  Fix up the typo and the reason why the typo didn't matter
before.  Also fix two places where rpcapi code had a return for a cast(), which
is now caught by the unit tests.

Closes-bug: #1272518
Change-Id: Ib5e3a002f6b0f7eb8dee8bd84bd53dbf817017f7
Merge "Fix a couple of unit test typos"
Merge "VMware: update the default 'task_poll_interval' time"
Merge commit 'refs/changes/08/60808/6' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/97/66597/4' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/79/69879/3' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch