Assignment from no return (#658)

* added unnecessary-dunder-call to pylintrc files; disabled for certain lines

in run_tests.py, exception thrown by 'git remote add origin' when the remote already exists will not exit

Signed-off-by: Mark Cohen <markcoh@amazon.com>

* updates to adhere to assignment-from-no-return lint

Signed-off-by: Mark Cohen <markcoh@amazon.com>

* simplified get_value_filter in Facet to return None
added assert to test get_value_filter returning None

Signed-off-by: Mark Cohen <markcoh@amazon.com>

* added option to output HTML test coverage locally from run_tests.py

returning None from test_faceted_search.Facet.get_value_filter

Signed-off-by: Mark Cohen <markcoh@amazon.com>

* added unused-variable lints; replaced unused variables with _ or referenced them

Signed-off-by: Mark Cohen <markcoh@amazon.com>

* updated CHANGELOG to point to the right PR

Signed-off-by: Mark Cohen <markcoh@amazon.com>

---------

Signed-off-by: Mark Cohen <markcoh@amazon.com>

.pylintrc

@@ -7,7 +7,9 @@ enable=line-too-long,
     missing-function-docstring,
     missing-param-doc,
     differing-param-doc,
-    unnecessary-dunder-call
+    unnecessary-dunder-call,
+    assignment-from-no-return,
+    unused-variable
 max-line-length=240
 good-names-rgxs=^[_a-z][_a-z0-9]?$