Prevent linkapps from creating duplicate aliases

`brew linkapps` was creating `MacVim` on the first run, then
`MacVim alias` on the second run.

Closes Homebrew#14955.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Library/Contributions/cmds/brew-linkapps.rb

@@ -32,7 +32,7 @@ def create_finder_alias(from, to)
       appname = File.basename(p, ".app")
       target = HOME_APPS+"/"+appname
       if File.exist? target
-        if File.symlink? target or finder_alias? target
+        if File.symlink?(target) || finder_alias?(target)
           system "rm", target
         else
           onoe "#{target} already exists, skipping."