Fix for Heat Salt Formula

Add correct stack_absent delete handling to prevent playing
in russian roulette. Now if stack is deleted before it's polled,
_poll_for_complete handle it correctly, without raising incorrect
exception.

Also dirty hack with sys.path.insert is removed.

Related-Issue: PROD-22102
Change-Id: I7f994c26304069052344c881b34e540e49fd5a32
diff --git a/_modules/heatv1/stack.py b/_modules/heatv1/stack.py
index ace3db0..001dc1d 100644
--- a/_modules/heatv1/stack.py
+++ b/_modules/heatv1/stack.py
@@ -1,6 +1,6 @@
 from yaml import safe_load
 import json
-import common
+from heatv1 import common
 try:
     from urllib.parse import urlencode
 except ImportError: