Python: remove (do not introduce) unused import

Author: yoff

python/ql/src/semmle/python/frameworks/Stdlib.qll

@@ -7,7 +7,6 @@ private import python
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.TaintTracking
 private import semmle.python.dataflow.new.RemoteFlowSources
-private import semmle.python.ApiGraphs
 private import semmle.python.Concepts
 private import PEP249