taglist: avoid v:true/v:false

autoload/airline/extensions/taglist.vim

@@ -11,10 +11,10 @@ endif
 function! airline#extensions#taglist#currenttag()
   " Update tag list if taglist is not loaded (else we get an empty tag name)
   " Load yegappan/taglist and vim-scripts/taglist.vim only once.
-  let tlist_updated = v:false
+  let tlist_updated = 0
   if !exists('*taglist#Tlist_Get_Tagname_By_Line()') && !exists('*Tlist_Get_Tagname_By_Line()')
       TlistUpdate
-      let tlist_updated = v:true
+      let tlist_updated = 1
   endif
   if  !tlist_updated && exists('*Tlist_Get_Filenames()')
       if stridx(Tlist_Get_Filenames(), expand('%:p')) < 0