examples.wrappers: Scripts to use with option --wrapper.

Scripts to use with command line option --wrapper.

* dummy.sh - Do nothing (use as a template).
* strace.sh - Run process on strace(1), output: strace.log.<pid>
* ltrace.sh - Run process on  ltrace(1), output: ltrace.log
* perf.sh   - Record process on perf(1), output: perf.data

Usage:

  avocado run datadir --wrapper examples/wrappers/strace.sh
  avocado run datadir \
              --wrapper examples/wrappers/ltrace.sh:make \
              --wrapper examples/wrappers/perf.sh:datadir \

Signed-off-by: Rudá Moura <rmoura@redhat.com>