Bug 1.8.15: USB connection issue

[_kris_]

MPE portable installation. If MPE has problem to connect to android smartphone by USB due to inproper settings in phone (no USB debugging, or bad USB transfer mode) then even if settings are fixed on phone MPE won't still connect - it will always display message connection couldn't be done even without trying. It's like some error flag in MPE was permanently set. The only way to solve it is to close and rerun MPE again.