Revert "mtp: fix error messages to be more consistent"
Revert "mtp: fix error messages to be more consistent"

This reverts commit 233faf72d10f9b60b4e0f33a281ac48b043cc28d
due to the string freeze.

gicmo/gvfs,gicmo/gvfs,gicmo/gvfs,gicmo/gvfs