decorator: Do not leak TrackerDecoratorInfo structs
decorator: Do not leak TrackerDecoratorInfo structs

Set the only reference to the decorator info as the GTask return
value, so it is definitely destroyed when the GTask itself is
unref()'ed.

outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker