Fixing tests in t_reactor.cc
Fixing tests in t_reactor.cc

One does not simply take a pointer to the stack (unless one is
programming in Rust).

Gangbiao/cvmfs,djw8605/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs,djw8605/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs,Gangbiao/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs,Gangbiao/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,Gangbiao/cvmfs,cvmfs/cvmfs,Gangbiao/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs