Signup-fixes

**DO NOT MERGE**

We'd like to regression test signup before merging it.

Some fixes for Special:Signup.
* [CONN-218](https://wikia-inc .atlassian.net/browse/CONN-218) -- adding `Database::commit()` after inserts to DB, 
* [CONN-421](https://wikia-inc.atlassian.net/browse/CONN-421) -- confirming e-mails once an account is created via FBConnect.