port r17402 from 1.2: yet more suppression

tools/valgrind/libc.suppr

@@ -55,4 +55,14 @@
    obj:/usr/lib/x86_64-linux-gnu/libltdl.so.7.3.1
    ...
 }
+{
+   <insert_a_suppression_name_here>
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   fun:malloc
+   obj:/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.22
+   fun:call_init.part.0
+   fun:_dl_init
+   obj:/lib/x86_64-linux-gnu/ld-2.21.so
+}