--headless broken with --enable-headless

[Tor Lillqvist]

> Now, on yet closer inspection, it is only the versions of CreateSalInstance
> for Android and --enable-headless (vcl/android/androidinst.cxx,
> vcl/headless/headlessinst.cxx, both based on SvpSalInstance) that do not
> lock the solar mutex -- while curiously enough both release it in
> DestroySalInstance.

Well, firstly I am not sure if this SalInstance code gets involved at
all currently in our Android app(s) (all GUI is done using Android
Java code, no VCL event loop etc is running), and secondly as far as I
know a properly written and working Android app should never exit
intentionally, calling DestroySalInstance and whatnot, so it shouldn't
matter anyway.  (Apps are not supposed to have any "quit"
functionality, they are left waiting in the background for an unbound
time when the user switches to another app, and It's the OS that kills
the app process eventually if it sees fit.)

--tml