OC-3242: Add new error message for fail in GetUserName
Revert "OC-3242: Add new error message for fail in GetUserName"

This reverts commit 564bbf7bb832881ee56fe90ea520b5f4becf491d.
OC-3242: Add new error message for fail in GetUserName. No changes in library reference
Merge pull request #436 from owncloud/add_fail_getUserName_error_message

OC-3242: Add new error message for fail in GetUserName