small fix for build_md_tests

Change-Id: I1ed5c85acaba91ddd639308d6d4365fdd2085207
diff --git a/tests/itests/docutests/build_md_test.py b/tests/itests/docutests/build_md_test.py
index f4b43b7..22e0f22 100644
--- a/tests/itests/docutests/build_md_test.py
+++ b/tests/itests/docutests/build_md_test.py
@@ -779,6 +779,9 @@
                     not_found = [p for p in expected_output if p not in
                                  pattern_found]
                     return -1, not_found  # failure
+                else:
+                    return -1, []
+
         except Exception as e:
             print 'Exception {} '.format(repr(e))
             return -1, []