Merge pull request #1021 from markdrayton/sym-mod-fix

python: handle null module in BPF.sym

src/python/bcc/__init__.py

@@ -1008,7 +1008,8 @@ class BPF(object):
         offset = "+0x%x" % offset if show_offset and name is not None else ""
         name = name or "[unknown]"
         name = name + offset
-        module = " [%s]" % os.path.basename(module) if show_module else ""
+        module = " [%s]" % os.path.basename(module) \
+            if show_module and module is not None else ""
         return name + module
 
     @staticmethod