Support GCC 4.7

Removed constructors inheritance.
Removed emplace use.

Change-Id: I45224e3232d39ff22f758c7e387be2c9aff5eae0
Reviewed-on: https://weave-review.googlesource.com/1606
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
diff --git a/src/notification/xmpp_iq_stanza_handler.cc b/src/notification/xmpp_iq_stanza_handler.cc
index 8753030..9ac4223 100644
--- a/src/notification/xmpp_iq_stanza_handler.cc
+++ b/src/notification/xmpp_iq_stanza_handler.cc
@@ -72,7 +72,7 @@
     const ResponseCallback& response_callback,
     const TimeoutCallback& timeout_callback) {
   // Remember the response callback to call later.
-  requests_.emplace(++last_request_id_, response_callback);
+  requests_.insert(std::make_pair(++last_request_id_, response_callback));
   // Schedule a time-out callback for this request.
   if (timeout < base::TimeDelta::Max()) {
     task_runner_->PostDelayedTask(