jdownloader.rb: install to appdir (#54628)

Casks/jdownloader.rb

@@ -4,13 +4,13 @@ cask 'jdownloader' do
 
   url 'http://installer.jdownloader.org/clean/JD2Setup.dmg',
       user_agent: :fake
-  name 'JDownloader 2'
+  name 'JDownloader'
   homepage 'http://jdownloader.org/'
 
   preflight do
     system_command "#{staged_path}/JDownloader Installer.app/Contents/MacOS/JavaApplicationStub",
                    args:         [
-                                   '-dir', staged_path.to_s,
+                                   '-dir', appdir.to_s,
                                    '-q',
                                    '-Dinstall4j.suppressStdout=true',
                                    '-Dinstall4j.debug=false',
@@ -20,7 +20,10 @@ cask 'jdownloader' do
                    print_stderr: false
   end
 
-  uninstall delete: '/Applications/JDownloader2.app'
+  uninstall delete: [
+                      "#{appdir}/JDownloader 2.0",
+                      "#{appdir}/JDownloader2.app",
+                    ]
 
   caveats do
     depends_on_java '8'