Enable Flake8 message E123

This looks for closing brackets at the wrong indentation.

.flake8

@@ -4,7 +4,6 @@ ignore =
     # The following errors were present when starting to use flake8; they need
     # to be triaged to determine which we should fix and which we should leave
     # permanently ignored
-    E123,
     E128,
     E131,
     E201,

build-data/osx/dmgsettings.py

@@ -52,7 +52,7 @@ def icon_from_app(app_path):
 icon_locations = {
     appname:        (240, 400),
     'Applications': (430, 400)
-    }
+}
 
 # .. Window configuration ......................................................
 
@@ -148,7 +148,7 @@ def icon_from_app(app_path):
     'label': 100,
     'version': 75,
     'comments': 300,
-    }
+}
 list_column_sort_directions = {
     'name': 'ascending',
     'date-modified': 'descending',
@@ -160,4 +160,4 @@ def icon_from_app(app_path):
     'label': 'ascending',
     'version': 'ascending',
     'comments': 'ascending',
-    }
+}