fix builds against sqlite 3.8.x

Summary: This seems to fix the build against SQLite 3.8.x versions
when using a Debug build.

This is just a proof of concept, since I don't
really know what I'm doing with SQLite or HHVM's code.

Is there any value in using RepoTxnQuery for PRAGMAs though?

It seems that SQLite doesn't like reading the value of journal_mode
in RepoTxnQuery, immediately after setting it.

The documentation for journal_mode only says:

"Note also that the journal_mode cannot be changed while a transaction is active."
http://www.sqlite.org/pragma.html#pragma_journal_mode
Closes https://github.com/facebook/hhvm/pull/4507

Reviewed By: @sgolemon

Differential Revision: D1757718

Signature: t1:1757718:1419833319:e19a0ffb9af315fa5d7eb69a40b56febc79e35e3
move HHVM version constant test to quick tests

Summary: This should stop issues like https://github.com/facebook/hhvm/issues/4521
from happening again.

This was suggested by@jwatzman in the same bug report.
It should also be applied to the 3.4 branch too.
Closes https://github.com/facebook/hhvm/pull/4530

Reviewed By: @JoelMarcey

Differential Revision: D1758492

Signature: t1:1758492:1419834081:8a545c709f117da8d468e15702cd39159909d1a9

Pulled By: @sgolemon