libevent: add granularity to ptest log

libevent: add granularity to ptest log

The libevent ptest used to report only a global pass or a fail result.
Count individual PASS, FAIL, SKIP results. The SKIP results now
include tests that are disabled in the libevent code.

libevent's ptest output did not comply with the automake-style output
"result: testname", and reported a FAIL status at the end of the test
run if any of the libevent tests failed. This patch makes the log
consistent with the automake style:

    PASS: http/cancel_by_host_no_ns
    PASS: http/cancel_inactive_server
    PASS: http/cancel_by_host_no_ns_inactive_server
    SKIPPED: http/cancel_by_host_server_timeout
    SKIPPED: http/cancel_server_timeout

and provides a summary as follows:

    === Test Summary ===
    TOTAL: 316
    PASSED: 300
    FAILED: 0
    SKIPPED: 16
    DURATION: 87
    END: /usr/lib/libevent/ptest

Signed-off-by: Trevor Gamblin <trevor.gamblin@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>