HACK: modules: bank: load framework plugins on iOS

On iOS, there's no folder plugins, and every plugins are located at the
Application root/Frameworks/ folder, so we need to probe this folder
instead of the plugins/ suffixed path. In addition, the library path
located by VLC will redirect to foo.app/Frameworks/vlccore.framework/vlc
which doesn't correspond to the correct path. It mostly affects 3.0.x
branch and not next 4.0 or more branches.

src/modules/bank.c

@@ -532,7 +532,12 @@ static void AllocateAllPlugins (vlc_object_t *p_this)
 #elif defined(__APPLE__) && defined(HAVE_DYNAMIC_PLUGINS) && TARGET_OS_IPHONE
     /* Redirect to the application folder, plugins/ is flattened. */
     char *vlcpath = config_GetLibDir ();
-    AllocatePluginPath (p_this, vlcpath, mode);
+    if (likely(vlcpath != NULL))
+    {
+        size_t len = strlen(vlcpath);
+        vlcpath[len - strlen("vlccore.framework/vlc")] = '\0';
+        AllocatePluginPath (p_this, vlcpath, mode);
+    }
     free(vlcpath);
 #else
     /* Contruct the special search path for system that have a relocatable