Required for https://github.com/owncloud/mail/pull/100#issuecomment-50266017

@karlitschek Backport for stable6 and stable7 requested.

- set password correctly in lost password

If an app upgrade failed, the core version will not be increased either
in the database. This will re-display the update page and make it
possible to redo the apps upgrade.

Note that any core repair routine must take into account that an update
might need to be redone again even though the core's DB state is already
the one of the new version.

Use the env:UserInstallation flag like https://github.com/owncloud/documents/blob/master/lib/converter.php.
This will stop the creating of multiple directories for document conversion in tmpDir.