Conf: reverted small change that could generate a bug

Signed-off-by: Nicola Vigano <nicola.vigano@esrf.fr>

zUtil_Conf/conf.example.xml

@@ -48,7 +48,7 @@
       -->
       <path>libgomp.so.1</path>
       <path>libpthread.so.0</path>
-      <path hostname="crunch,rnice*,gp*">libstdc++.so.6</path>
+      <path hostname="crunch,rnice*,gp*">/usr/lib/x86_64-linux-gnu/libstdc++.so.6</path>
     </preload>
   </matlab>