Actually fix info_cache healing lazy load

system_metadata is still being lazy loaded as a part of healing the
instance info_cache.  A previous attempt to fix this issue missed the
more important call.

It's actually more efficient to not load the system_metadata when getting
the list and allow the 1 instance to lazy load.  For the cached instances,
we will ask for system_metadata when getting a fresh copy from the DB.

Fixes bug 1223969

Change-Id: Ib95e868135ed2b36af7ddbcfb8d5905bfe14d1fe
Merge "Actually fix info_cache healing lazy load"