valgrind: add valgrind suppression for Fedora 22

valgrind: add valgrind suppression for Fedora 22

Fixes for example valgrind tests for ./libnm/tests/test-nm-client:

    ==25772== Conditional jump or move depends on uninitialised value(s)
    ==25772==    at 0x40198D8: index (strchr.S:106)
    ==25772==    by 0x400777C: expand_dynamic_string_token (dl-load.c:369)
    ==25772==    by 0x400777C: fillin_rpath (dl-load.c:439)
    ==25772==    by 0x4007FCF: _dl_init_paths (dl-load.c:816)
    ==25772==    by 0x4002F38: dl_main (rtld.c:1194)
    ==25772==    by 0x401750F: _dl_sysdep_start (dl-sysdep.c:249)
    ==25772==    by 0x4004C20: _dl_start_final (rtld.c:306)
    ==25772==    by 0x4004C20: _dl_start (rtld.c:412)
    ==25772==    by 0x4000C97: ??? (in /usr/lib64/ld-2.21.so)
    ==25772==    by 0x1: ???
    ==25772==    by 0xFFEFFF6B2: ???
    ==25772==    by 0xFFEFFF6EF: ???
    ==25772==
    {
       <insert_a_suppression_name_here>
       Memcheck:Cond
       fun:index
       fun:expand_dynamic_string_token
       fun:fillin_rpath
       fun:_dl_init_paths
       fun:dl_main
       fun:_dl_sysdep_start
       fun:_dl_start_final
       fun:_dl_start
       obj:/usr/lib64/ld-2.21.so
       obj:*
       obj:*
       obj:*
    }