Fixes logic error in filter search

The search was using !$.inArray when the expression should be $.inArray === -1 since it returns the index of the value in the array.
Also tidied up the code so it is easier to read.
Fixes #1918

modules/system/assets/ui/js/filter.js

@@ -302,15 +302,13 @@
          * Ensure any active items do not appear in the search results
          */
         if (items.active.length) {
-            var compareFunc = function(a, b) { return a.id == b.id },
-                inArrayFunc = function(elem, array, testFunc) {
-                    var i = array.length
-                    do { if (i-- === 0) return i } while (testFunc(array[i], elem))
-                    return i
-                }
+            var activeIds = []
+            $.each(items.active, function (key, obj) {
+                activeIds.push(obj.id)
+            })
 
             filtered = $.grep(available, function(item) {
-                return !inArrayFunc(item, items.active, compareFunc)
+                return $.inArray(item.id, activeIds) === -1
             })
         }
         else {

modules/system/assets/ui/storm-min.js

@@ -2974,10 +2974,9 @@ if(!this.scopeValues[this.activeScopeName])
 return
 var
 self=this,filtered=[],items=this.scopeValues[scopeName]
-if(items.active.length){var compareFunc=function(a,b){return a.id==b.id},inArrayFunc=function(elem,array,testFunc){var i=array.length
-do{if(i--===0)return i}while(testFunc(array[i],elem))
-return i}
-filtered=$.grep(available,function(item){return!inArrayFunc(item,items.active,compareFunc)})}
+if(items.active.length){var activeIds=[]
+$.each(items.active,function(key,obj){activeIds.push(obj.id)})
+filtered=$.grep(available,function(item){return $.inArray(item.id,activeIds)===-1})}
 else{filtered=available}
 var container=$('#controlFilterPopover .filter-items > ul').empty()
 self.addItemsToListElement(container,filtered)}