Clean-up the upgrade path: system

Do we want to merge the changes to 7060 with this issue: #895176: Upgrade fails because of integrity constraint violation in system_update_7060 ?

I'm unsure about the conditional creation of fields, the other issue (and the duplicate one I linked in #10) has shown that this is a problem if anything goes wrong with the update function and someone tries it a second time (Maybe he messed around manually with the schema), it explodes.

I guess we could actually make the _field_* helper functions intelligent enough to silently handle the case (maybe return TRUE/FALSE?) when a field already exists? Instead of throwing an ugly exception...

There's a patch here.

Discussed #3 with chx and we came to the conclusion that the best thing to do is separate out the field creation calls into their own update function so failures during processing of the files doesn't lead to re-creating the fields.

#2: 898584-upgrade-cleanup-system.patch queued for re-testing.

#2: 898584-upgrade-cleanup-system.patch queued for re-testing.

Sorry for the double retest. Here's a patch that uses the new update helper function names and removes the fixes to 7060 in favor of #895176: Upgrade fails because of integrity constraint violation in system_update_7060, which I hope to have a new patch for shortly as well.

Should this use variable_get('theme_default', 'garland') rather than 'bartik', since this runs on a site upgrading from Drupal 6?

now update node get types return type objects not type strings. Trivial fix after realizin' that.

Ah. Changed bartik to garland.

7060 is handled elsewhere, garland change looks good, RTBC.

Committed #16 to HEAD. Thanks!