Breakpoint in shared library does not work on mips-irix.

Breakpoint in shared library does not work on mips-irix.

        * procfs.c: #include "observer.h".
        (procfs_inferior_created): New function, moving here the code
        which unsets the syssgi syscall-exit notifications.
        (procfs_create_inferior): Remove the code which unsets the syssgi
        syscall-exit notifications. It is too early to do this here.
        (_initialize_procfs): Attach the procfs_inferior_created observer.