lo_startmain drops the SolarMutex without taking it, interestingly.

Change-Id: I2280e2fa6acb8739f970983032db72a8241d1c4f
Reviewed-on: https://gerrit.libreoffice.org/71742Reviewed-by: Jan Holesovsky <kendy@collabora.com>
Tested-by: Jan Holesovsky <kendy@collabora.com>