Fixes some typos that cause errors

libs/modules/RTC.bundle.js

      */
     bindDataChannelListener: function (peerConnection) {
         if(!config.openSctp)
-            retrun;
+            return;
 
         peerConnection.ondatachannel = this.onDataChannel;
 

libs/modules/xmpp.bundle.js

             var self = this;
             // Remove old ssrcs coming from the jid
             Object.keys(this.ssrc2jid).forEach(function (ssrc) {
-                if (self.ssrc2jid[ssrc] == jid) {
+                if (self.ssrc2jid[ssrc] == from) {
                     delete self.ssrc2jid[ssrc];
                 }
             });

modules/RTC/DataChannels.js

      */
     bindDataChannelListener: function (peerConnection) {
         if(!config.openSctp)
-            retrun;
+            return;
 
         peerConnection.ondatachannel = this.onDataChannel;
 

modules/xmpp/strophe.emuc.js

             var self = this;
             // Remove old ssrcs coming from the jid
             Object.keys(this.ssrc2jid).forEach(function (ssrc) {
-                if (self.ssrc2jid[ssrc] == jid) {
+                if (self.ssrc2jid[ssrc] == from) {
                     delete self.ssrc2jid[ssrc];
                 }
             });