(recv_conn): set `wait_on_pid' instead of looping on waitpid here
also. This should solve the problem of kxd looping which was caused
by the signal handler getting invoked before this waitpid and reaping
the child leaving this poor loop without any child
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@6894 ec53bebd-3082-4978-b11e-865c3cabbd6b