1 is not safe, unusual PID value

[Askar Safin]

In jobs.c we see:

#if defined (RECYCLES_PIDS)
      if (last_asynchronous_pid == mypid)
        /* Avoid pid aliasing.  1 seems like a safe, unusual pid value. */
        last_asynchronous_pid = 1;
#endif

1 is not safe, unusual PID value, because:

1. Linux kernel sometimes start with option "init=/bin/bash"
2. Embeged systems offen have init, written in bash or /bin/sh, which is 
symlink to bash
3. Mostly all inits of initrd/initramfs written in shell, which may be symlink 
to bash

Please, fix