Rename Event according to Vim conventions

autoload/vundle.vim

@@ -36,6 +36,6 @@ endf
 
 augroup bundle#command-t
   au!
-  au User PreInstall  echo 'ok'
-  au User PostInstall !cd ruby/command-t && ruby extconf.rb && make clean && make
+  au User BundleInstallPre  echo 'ok'
+  au User BundleInstallPost !cd ruby/command-t && ruby extconf.rb && make clean && make
 augroup END

autoload/vundle/installer.vim

@@ -79,7 +79,7 @@ func! s:sync(bang, bundle) abort
 
   if 0 <= index(s:load_augroups(), aug_name)
     lcd `=a:bundle.path()`
-    exec 'doautocmd '.l:aug_name.' User PostInstall'
+    exec 'doautocmd '.l:aug_name.' User BundleInstallPost'
     lcd `=cwd`
   endif