Revert "sipaccountbase: use ipv6 address for TURN"

This reverts commit 6ce8a7ce.

Reason for revert: Some problems with ipv4 only networks

Change-Id: Id038c0d60adb3c2fa37d23bb7561c00a30c5aac1

src/sip/sipaccountbase.cpp

@@ -480,7 +480,7 @@ SIPAccountBase::getIceOptions() const noexcept
         }
         if (cacheTurnV6_ && *cacheTurnV6_) {
             opts.turnServers.emplace_back(TurnServerInfo()
-                                              .setUri(cacheTurnV6_->toString(true))
+                                              .setUri(cacheTurnV4_->toString(true))
                                               .setUsername(turnServerUserName_)
                                               .setPassword(turnServerPwd_)
                                               .setRealm(turnServerRealm_));