SYSDB: SSS_LDB_SEARCH - macro around ldb_search
This patch amends previous patch 5153e8b9793dea1e212ca08af0f77ea1d023cbb7.
Macro SSS_LDB_SEARCH is used instead of using fuction sss_ldb_search as
a wrapper around ldb_search which could lead to premature expansion of
variadic parameters.
Part of solution for:
https://fedorahosted.org/sssd/ticket/1991
Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>