remove magic dropdown positioning for fixed bottom; folks should set this as needed with .dropup modifier

scss/_dropdown.scss

@@ -150,10 +150,8 @@
 // Allow for dropdowns to go bottom up (aka, dropup-menu)
 //
 // Just add .dropup after the standard .dropdown class and you're set.
-// TODO: abstract this so that the navbar fixed styles are not placed here?
 
-.dropup,
-.navbar-fixed-bottom .dropdown {
+.dropup {
   // Reverse the caret
   .caret {
     content: "";