Remove iostream which causes a new static initializer
TBR=pthatcher@webrtc.org
BUG=webrtc:4576

Review URL: https://codereview.webrtc.org/1205553002.

Cr-Commit-Position: refs/heads/master@{#9488}
diff --git a/webrtc/p2p/stunprober/stunprober.cc b/webrtc/p2p/stunprober/stunprober.cc
index 4a33444..49f231b 100644
--- a/webrtc/p2p/stunprober/stunprober.cc
+++ b/webrtc/p2p/stunprober/stunprober.cc
@@ -8,7 +8,6 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include <iostream>
 #include <map>
 #include <set>
 #include <string>