String.Trim(string, " ") can only get ride of the blank, but actully we need to remove all leading and trailing white space include "\t" for example. Prior to this patch, one can login with "[Tab][Tab]username", and it will not be consider as the same with "username". Signed-off-by: Hu Keping <hukeping@huawei.com> Upstream-commit: e9602f3561b78313c4d474a8d950f7cc562637e8 Component: engine