Modify elf/tst-audit9.c to use test-skeleton.c

This test was skipped by the use-test-skeleton conversion script
[29955b5d] because the definition of `main' did not begin according to
the GNU formatting style that the script assumed.

ChangeLog:

2015-07-09  Arjun Shankar  <arjun.is@lostca.se>

	* elf/tst-audit9.c (main): Converted to ...
	(do_test): ... this.
	(TEST_FUNCTION): New macro.
	Include test-skeleton.c.