[libvirt] fix for crash in NPIV code

[Dave Allan]

DV found a place in the NPIV code that was freeing the wrong thing in 
the error case causing a segfault.  The patch to fix it follows.

Dave


diff --git a/src/node_device.c b/src/node_device.c
index cd9f0ef..c5b839b 100644
--- a/src/node_device.c
+++ b/src/node_device.c
@@ -489,8 +489,8 @@ get_wwns(virConnectPtr conn,

      if (*wwnn == NULL || *wwpn == NULL) {
          /* Free the other one, if allocated... */
-        VIR_FREE(wwnn);
-        VIR_FREE(wwpn);
+        VIR_FREE(*wwnn);
+        VIR_FREE(*wwpn);
          ret = -1;
          virReportOOMError(conn);
      }