Take into account for mounts that has weird flags that is not accounted for

diff --git a/Collie.lua b/Collie.lua
index a41c2ca..61e2410 100644
--- a/Collie.lua
+++ b/Collie.lua
@@ -5,6 +5,7 @@ local filterFlags = {
 	['flying'] = true,
 	['ground'] = true,
 	['combined'] = true,
+	['unknown'] = true,
 }

 local Search = CreateFrame('EditBox', 'MountSearch', MountJournal, 'SearchBoxTemplate')
@@ -23,7 +24,9 @@ Search:SetScript('OnTextChanged', function(self)
 end)

 local mounts = {}
-local function BuildMounts()
+local function BuildMounts(self, event)
+	if(event and event ~= 'COMPANION_LEARNED') then return end
+
 	for index = 1, GetNumCompanions('MOUNT') do
 		local id, name, _, _, _, flag = GetCompanionInfo('MOUNT', index)
 		if(flag == 12) then
@@ -34,6 +37,8 @@ local function BuildMounts()
 			mounts[index] = 'ground'
 		elseif(flag == 31) then
 			mounts[index] = 'combined'
+		else
+			mounts[index] = 'unknown'
 		end

 		-- exceptions
@@ -164,6 +169,15 @@ local function CreateDropDown()
 		MountJournal_UpdateMountList()
 	end
 	UIDropDownMenu_AddButton(info)
+
+	info.text = 'Unknown'
+	info.checked = filterFlags.unknown
+	info.func = function(...)
+		local _, _, _, enabled = ...
+		filterFlags.unknown = enabled
+		MountJournal_UpdateMountList()
+	end
+	UIDropDownMenu_AddButton(info)
 end

 local FilterDropDown = CreateFrame('Frame')