Bug 825275: Fix DNS cache enumerator crash. r=sworkman

netwerk/dns/nsHostResolver.cpp

@@ -1077,6 +1077,7 @@ CacheEntryEnumerator(PLDHashTable *table, PLDHashEntryHdr *entry,
             if (NetAddrToString(addr, buf, sizeof(buf))) {
                 info.hostaddr.AppendElement(buf);
             }
+            addr = nullptr;
             addrElement = addrElement->getNext();
             if (addrElement) {
                 addr = &addrElement->mAddress;