Android: Fixed opening previously closed joystick (thanks, Sylvain!).

Fixes Bugzilla #3408.
diff --git a/src/joystick/android/SDL_sysjoystick.c b/src/joystick/android/SDL_sysjoystick.c
index 6ef16a9..89b8163 100644
--- a/src/joystick/android/SDL_sysjoystick.c
+++ b/src/joystick/android/SDL_sysjoystick.c
@@ -538,6 +538,8 @@
 void
 SDL_SYS_JoystickClose(SDL_Joystick * joystick)
 {
+    SDL_joylist_item *item = (SDL_joylist_item *) joystick->hwdata;
+    item->joystick = NULL;
 }
 
 /* Function to perform any system-specific joystick related cleanup */