busybox:
 * fix build problem with uClibc-0.9.28 and busybox feature "Enable sanity check on user/group names in adduser and addgroup" ({{{FEATURE_CHECK_NAMES}}}, disabled by default)
 * refs #2550


git-svn-id: file:///var/svn/freetz/trunk@12450 149334a1-2f27-0410-a3b9-fc62619ac1e6