Valgrind: add a suppression file for hwloc, kindly submitted by Brice Goglin.

tools/valgrind/hwloc.suppr

@@ -0,0 +1,20 @@
+{
+   zlib doesn't cleanup
+   Memcheck:Cond
+   fun:inflateReset2
+   fun:inflateInit2_
+}
+{
+   hwloc cannot free the global parser (xmlCleanupParser) because other threads may be using it
+   Memcheck:Leak
+   ...
+   fun:xmlInitParser
+}
+{
+   hwloc cannot free the global xml dict RMutex because it cannot call xmlCleanupParser
+   Memcheck:Leak
+   fun:malloc
+   fun:xmlNewRMutex
+   ...
+   fun:xmlDictCreate
+}