Revert "Issue #2266997 by cweagans - Do not automatically enable update module when installing a site."

This reverts commit 70622f6e.

Without this change some tasks may fail with error: Drush command terminated abnormally due to an unrecoverable error. Error: Call to undefined function t() in /data/disk/o1/.drush/provision/platform/verify.provision.inc, line 92

Issue #1217486 by netdream - Add o_contrib symlinks (if missing) on platform Verify task (only for custom platforms)

Issue #1217486 by netdream - Add o_contrib symlinks (if missing) on platform Verify task (Provision part)

Use the same trick with modules/local-allow.info to temporarily make civicrm.settings.php writable, if exists.

Do not force old_short_name if already set in db/drushrc, to avoid overriding old_short_name defined in the profile file directly.

The cache_form bin is excluded in drupal_flush_all_caches() but if not purged, it may break tasks with mysterious errors thanks to garbage collected.

Otherwise web server can't write there, so even if we use Drush for cron, and it will run as an Aegir backend user, which has the write access there (and also limited shell user can write there) the module itself will refuse to work on scheduled cron run, because the backup directories are expected to be writable by the web server. This is required also when standard wget method for cron is used.

Fix for recent changes in the upstream Provision code: provision-login_reset is now provision-login-reset.

Issue #1681564 by lsolesen - Commerce Kickstart 2.x does not use body_summary in field_data_body and field_revision_body.