Reload PPA's expanded section for a source after build status updated

Currently each source package listed on a PPA page has an expandable section that is loaded via ajax the first time it is expanded.

This extra information includes information about the current build statuses. The build statuses are updated via ajax on the PPA page, but the expandable section is not currently updated after it's initial load.

The solution should be as simple as doing the following when a source package's build status summary changes:

if extra_info_node is not null:
  if it's currently expanded
    close it
  reset it back to null
  re-expand it if it was open initially.