adb: remove SendConnectOnHost.

This logic appears to be racy, and it shouldn't actually be needed, if
our devices follow the USB spec. Use libusb_set_interface_alt_setting
on device initialization as well, to add one more thing that should
reset the data toggles.

Bug: http://b/32952319
Test: python test_device.py
Change-Id: I392198af3d72c524b893e5056afa2b4617cea49c