Fix two debugger attach bugs.

 - orte_debugger_init_after_spawn was not being called for debuggers that
   use the MPIR_attach_fifo to co-locate debugger daemons.
 - MPIR_Breakpoint was not getting called if a debugger reattached. Add
   a job state (ORTE_JOB_STATE_DEBUGGER_DETACH) to reset mpir_breakpoint_fired
   to false when a debugger detaches to ensure MPIR_Breakpoint is called if
   another debugger attaches. Tested with STAT 2.0/launchmon 1.0.

cmr:v1.7