Move lock earlier in the call sequence

Move lock earlier in the call sequence

fctx->state should be read with the lock held.

    1559        /*
    1560         * Caller must be holding the fctx lock.
    1561         */

    CID 468796: (#1 of 1): Data race condition (MISSING_LOCK)
    1. missing_lock: Accessing fctx->state without holding lock fetchctx.lock.
       Elsewhere, fetchctx.state is written to with fetchctx.lock held 2 out of 2 times.
    1562        REQUIRE(fctx->state == fetchstate_done);
    1563
    1564        FCTXTRACE("sendevents");
    1565
    1566        LOCK(&fctx->lock);
    1567