Remove unnecessary defined('ENVIRONMENT') checks

As suggested in issue #2134 & PR #2149
diff --git a/application/config/mimes.php b/application/config/mimes.php
index ac7bfaf..dfa9f24 100644
--- a/application/config/mimes.php
+++ b/application/config/mimes.php
@@ -176,4 +176,4 @@
 );
 
 /* End of file mimes.php */
-/* Location: ./application/config/mimes.php */
+/* Location: ./application/config/mimes.php */
\ No newline at end of file