UTIL: Fix order of header files.
    
    The older version of glibc and different implementations of libs
    requires feature macros for enabling function getline.
    
           getline(), getdelim():
               Since glibc 2.10:
                   _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
               Before glibc 2.10:
                   _GNU_SOURCE
    
    All feature macros are in header file config.h and are detected by configure
    script. The header file config.h was included after few other header files.
    The problem is that header files stdio.h is included just once and
    is included from many external header files. We need to include config.h
    before any other header file to prevent problems.
    
    src/util/nscd.c: In function ‘sss_nscd_parse_conf’:
    src/util/nscd.c:150: error: implicit declaration of function ‘getline’
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
    (cherry picked from commit b3007e32fa5d6b722f3aaaf9fe7593103cb443c3)