test: Fix “local variable 'e' is assigned to but never used”

flake8 F841 lints, as of flake8 3.6.0

test/functional/feature_assumevalid.py

@@ -72,7 +72,7 @@ class AssumeValidTest(BitcoinTestFramework):
                 break
             try:
                 p2p_conn.send_message(msg_block(self.blocks[i]))
-            except IOError as e:
+            except IOError:
                 assert not p2p_conn.is_connected
                 break
 

test/functional/test_framework/test_framework.py

@@ -192,18 +192,18 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
             self.setup_network()
             self.run_test()
             success = TestStatus.PASSED
-        except JSONRPCException as e:
+        except JSONRPCException:
             self.log.exception("JSONRPC error")
         except SkipTest as e:
             self.log.warning("Test Skipped: %s" % e.message)
             success = TestStatus.SKIPPED
-        except AssertionError as e:
+        except AssertionError:
             self.log.exception("Assertion failed")
-        except KeyError as e:
+        except KeyError:
             self.log.exception("Key error")
-        except Exception as e:
+        except Exception:
             self.log.exception("Unexpected exception caught during testing")
-        except KeyboardInterrupt as e:
+        except KeyboardInterrupt:
             self.log.warning("Exiting after keyboard interrupt")
 
         if success == TestStatus.FAILED and self.options.pdbonfailure: