[Vala] Change in 0.23.1 for array ownership and .length parameter

[Jim Nelson <jim yorba org>]

Just wanted to give everyone a head's-up about a change that appeared 
in Vala 0.23.  Previously you could do this in Vala:

uint8[] ar = new uint8[10];
// ... fill ar with interesting bytes ...
process((owned) ar, ar.length);

... where process() takes an array and a length field (sometimes 
because an array might have a "filled" count versus it's allocated 
length).  Before 0.23 the above worked, but now ar.length will be 
zeroed out before it's passed to process():

https://bugzilla.gnome.org/show_bug.cgi?id=721001

I found a few instances of this pattern in our code and thought others 
might want to be alerted about it as well.

-- Jim