Fixed comparing columns with requested matching column when in import

Ok I don't know how else to explain it. It fixes an error where
a string comparison was .lower() on one side but not the other.

Author: bufke

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name = "django-simple-import",
-    version = "1.14",
+    version = "1.15",
     author = "David Burke",
     author_email = "david@burkesoftware.com",
     description = ("A Django import tool easy enough your users could use it"),

simple_import/views.py

@@ -342,7 +342,7 @@ def do_import(request, import_log_id):
         header_row_field_names += [match.field_name]
         header_row_default += [match.default_value]
         header_row_null_on_empty += [match.null_on_empty]
-        if key_column_name == cell.lower():
+        if key_column_name.lower() == cell.lower():
             key_index = i
 
     with transaction.commit_manually():