ktest: Have the testing tmp dir include machine name

As multiple tests may be executed by the same server, have the test
machine name add uniqueness to the value of the temp directory.
Otherwise the temp directories may overwrite each other's tests.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --cc tools/testing/ktest/ktest.pl
Simple merge

diff --cc tools/testing/ktest/sample.conf
Simple merge