Minetest: Android crash on startup

[Wayward1]

With the latest git, the Android app crashes with

```

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2017-05-08 21:14:43: ERROR[Main]: Subgame specified in default_game [minetest] is invalid.
2017-05-08 21:14:47: ERROR[Main]: GUIEngine: execution of menu script failed: Failed to load and run script from /storage/emulated/0/Minetest/builtin/init.lua:
2017-05-08 21:14:47: ERROR[Main]: /storage/emulated/0/Minetest/builtin/mainmenu/tab_simple_main.lua:217: 'end' expected (to close 'function' at line 104) near ''
2017-05-08 21:14:47: ERROR[Main]: stack traceback:
2017-05-08 21:14:47: ERROR[Main]: [C]: in function 'dofile'
2017-05-08 21:14:47: ERROR[Main]: ...torage/emulated/0/Minetest/builtin/mainmenu/init.lua:57: in main chunk
2017-05-08 21:14:47: ERROR[Main]: [C]: in function 'dofile'
2017-05-08 21:14:47: ERROR[Main]: /storage/emulated/0/Minetest/builtin/init.lua:45: in main chunk
2017-05-08 21:14:47: ERROR[Main]: No future without main menu!

[paramat]

'No future without main menu!'

[SmallJoker]

5736 merged.