Various python3 related changes

- Use relative import for grgsm's modules
- Convert map to list
- Remove the hier_block.py workaround as as gnuradio 3.7 is no longer
  supported in this branch

Change-Id: I5ca8fd340823996e8c444aaf18ddacd85c92ab1c
diff --git a/python/receiver/fcch_detector.py b/python/receiver/fcch_detector.py
index 81438e2..9b787c2 100644
--- a/python/receiver/fcch_detector.py
+++ b/python/receiver/fcch_detector.py
@@ -36,10 +36,10 @@
 from gnuradio.filter import firdes
 import grgsm
 
-class fcch_detector(grgsm.hier_block):
+class fcch_detector(gr.hier_block2):
 
     def __init__(self, OSR=4):
-        grgsm.hier_block.__init__(
+        gr.hier_block2.__init__(
             self, "FCCH bursts detector",
             gr.io_signature(1, 1, gr.sizeof_gr_complex*1),
             gr.io_signature(1, 1, gr.sizeof_gr_complex*1),