TOOLS: sss_mc_refresh_nested_group short/fqname usage
We use shortname to refresh memory cache, but in case of nested groups,
we used internal_fqname to refresh parent groups.
We also wrongly used the shortname for sysdb_search operation.
Which caused error message to be printed when sss_usermod -a or
sss_groupmod -a where called.
Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>