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>

tools/testing/ktest/ktest.pl

@@ -27,7 +27,7 @@ $default{"TEST_TYPE"}		= "test";
 $default{"BUILD_TYPE"}		= "randconfig";
 $default{"MAKE_CMD"}		= "make";
 $default{"TIMEOUT"}		= 120;
-$default{"TMP_DIR"}		= "/tmp/ktest";
+$default{"TMP_DIR"}		= "/tmp/ktest/\${MACHINE}";
 $default{"SLEEP_TIME"}		= 60;	# sleep time between tests
 $default{"BUILD_NOCLEAN"}	= 0;
 $default{"REBOOT_ON_ERROR"}	= 0;

tools/testing/ktest/sample.conf

@@ -392,8 +392,8 @@
 #ADD_CONFIG = /home/test/config-broken
 
 # The location on the host where to write temp files
-# (default /tmp/ktest)
-#TMP_DIR = /tmp/ktest
+# (default /tmp/ktest/${MACHINE})
+#TMP_DIR = /tmp/ktest/${MACHINE}
 
 # Optional log file to write the status (recommended)
 #  Note, this is a DEFAULT section only option.