Add a systemtap script for watching QEMU monitor interactions

Add a systemtap script for watching QEMU monitor interactions

This change adds some systemtap/dtrace probes to the QEMU monitor
client code. In particular it allows watching of all operations
for a VM

* examples/systemtap/qemu-monitor.stp: Watch all monitor commands
* src/Makefile.am: Passing libdir/bindir/sbindir to dtrace2systemtap.pl
* src/dtrace2systemtap.pl: Accept libdir/bindir/sbindir as args
  and look for '# binary:' comment to mark probes against libvirtd
  vs libvirt.so
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor_json.c,
  src/qemu/qemu_monitor_text.c: Add probes for key functions