tests: remove temporary directory on setup and teardown

Change-Id: I012b11a9d6a46769dc5f6e388ab6bd3f2644607e
diff --git a/tests/wscript b/tests/wscript
index 956fd0d..4092db1 100644
--- a/tests/wscript
+++ b/tests/wscript
@@ -28,7 +28,7 @@
 def build(bld):
     # Unit tests
     if bld.env.WITH_TESTS:
-        tmpdir = 'UNIT_TESTS_TMPDIR="%s"' % bld.bldnode.make_node('tmp-files')
+        tmpdir = 'UNIT_TESTS_TMPDIR="%s"' % bld.bldnode.make_node('tests-tmp')
 
         # common test objects
         bld.objects(