Fix a simple buffer overflow - 16 bytes isn't enough to hold
the string representation of a gulong on x86_64. I guess the
intent was to generate a 32 bit random key, so let's do that.
Only matters if anyone ever ports the sink to 1.x
https://bugzilla.gnome.org/show_bug.cgi?id=676524
Original commit message from CVS:
* ext/apexsink/gstapexraop.c: (gst_apexraop_connect),
(gst_apexraop_set_volume):
Fix format string compiler warnings.