[SSSD] [PATCH] Fix compilation warning

[Jakub Hrozek]

Sorry, one of my patches introduced a compilation warning:

CC       src/providers/krb5/krb5_child_handler.lo
/home/remote/jhrozek/devel/sssd/src/providers/krb5/krb5_common.c:928:14: warning:
assigning to 'char *'
      from 'const char *' discards qualifiers
[-Wincompatible-pointer-types-discards-qualifiers]
        name = username;
             ^ ~~~~~~~~
 
I have pushed the attached one-liner to fix the warning.