assertion failed when using "-usb" option

SUMMARY:
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Description: Latest 'master' makes it impossible to use "-usb" command line on any target
Host platform: Linux x86-64
Guest platform: probably all (at least x86-64, i386, arm and ppc)

REPRODUCE:
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How to reproduce:
1. Run the following command:
$ qemu-system-x86_64 -usb

Expected result:
Starting virtual machine with empty configuration

Actual result:
Qemu crashes with following message:

qemu-system-x86_64: /home/mplucinski/Developer/Open_Source/qemu/qemu.git/util/qemu-option.c:387: qemu_opt_get_bool_helper: Assertion `opt->desc && opt->desc->type == QEMU_OPT_BOOL' failed.
Aborted

MORE INFORMATION:
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Same happens when trying to run other target, e.g.
$ qemu-system-i386 -usb
$ qemu-system-arm -machine kmz -usb

First commit where the issue occurs (bisection result): 49d2e648e8087d154d8bf8b91f27c8e05e79d5a6