Coverity requires that allocated objects (use of new)
are directly release, by foo = null;
The gc will do this automatically at some point in time,
so this will simply release the resource a bit earlier,
which can save problems if the function is called in a tight
loop.

Updated to add close() before clearing the variable, this would
normally be done by gc, but now a bit earlier. The assignment to
null is not needed specifically, but Coverity calls it a leak if
not assigned.

Forgot .close();

Change-Id: Id273e7f36778c1691b260d28e741c6e32148c9d9