make test: fix broken DEBUG=gdb* options

Change-Id: I5d80982eeab78a629760f567eda3b1539d96e3a8
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/test/framework.py b/test/framework.py
index 58b76bb..89d95cb 100644
--- a/test/framework.py
+++ b/test/framework.py
@@ -115,6 +115,10 @@
         """
         Write current test tmpdir & desc to keep-alive pipe to signal liveness
         """
+        if self.pipe is None:
+            # if not running forked..
+            return
+
         if isclass(test):
             desc = test.__name__
         else:
@@ -901,8 +905,8 @@
         """Class maintaining the results of the tests"""
         return VppTestResult
 
-    def __init__(self, pipe, stream=sys.stderr, descriptions=True, verbosity=1,
-                 failfast=False, buffer=False, resultclass=None):
+    def __init__(self, pipe=None, stream=sys.stderr, descriptions=True,
+                 verbosity=1, failfast=False, buffer=False, resultclass=None):
         # ignore stream setting here, use hard-coded stdout to be in sync
         # with prints from VppTestCase methods ...
         super(VppTestRunner, self).__init__(sys.stdout, descriptions,