Stop setting usb config from recovery init script

We used to set sys.usb.config to adb in the init script. And the purpose
is to start adbd. This is a duplicate of code because we always check and
reset the usb config in recovery_main.

Test: check adbd starts
Change-Id: I6e2842ff8aebf6ccf3bd3f2ae85323899a2b9de4