Fixes issue with switching desktop stream.

libs/strophe/strophe.jingle.sdp.js

 };
 
 function SDPDiffer(mySDP, otherSDP) {
-    this.mySDP = new SDP(mySDP);
-    this.otherSDP = new SDP(otherSDP);
+    this.mySDP = mySDP;
+    this.otherSDP = otherSDP;
 }
 
 /**

libs/strophe/strophe.jingle.session.js

  */
 JingleSession.prototype.notifyMySSRCUpdate = function (old_sdp, new_sdp) {
 
-    if (!(this.peerconnection.signalingState == 'stable' && this.peerconnection.iceConnectionState == 'connected')){
+    if (!(this.peerconnection.signalingState == 'stable' &&
+        this.peerconnection.iceConnectionState == 'connected')){
         console.log("Too early to send updates");
         return;
     }
 
-    // send source-add IQ.
-    var sdpDiffer = new SDPDiffer(old_sdp, new_sdp);
-    var add = $iq({to: self.peerjid, type: 'set'})
+    // send source-remove IQ.
+    sdpDiffer = new SDPDiffer(new_sdp, old_sdp);
+    var remove = $iq({to: this.peerjid, type: 'set'})
         .c('jingle', {
             xmlns: 'urn:xmpp:jingle:1',
-            action: 'source-add',
-            initiator: self.initiator,
-            sid: self.sid
+            action: 'source-remove',
+            initiator: this.initiator,
+            sid: this.sid
         }
     );
-    var added = sdpDiffer.toJingle(add);
-    if (added) {
-        this.connection.sendIQ(add,
+    var removed = sdpDiffer.toJingle(remove);
+    if (removed) {
+        this.connection.sendIQ(remove,
             function (res) {
-                console.info('got add result', res);
+                console.info('got remove result', res);
             },
             function (err) {
-                console.error('got add error', err);
+                console.error('got remove error', err);
             }
         );
     } else {
-        console.log('addition not necessary');
+        console.log('removal not necessary');
     }
 
-    // send source-remove IQ.
-    sdpDiffer = new SDPDiffer(new_sdp, old_sdp);
-    var remove = $iq({to: self.peerjid, type: 'set'})
+    // send source-add IQ.
+    var sdpDiffer = new SDPDiffer(old_sdp, new_sdp);
+    var add = $iq({to: this.peerjid, type: 'set'})
         .c('jingle', {
             xmlns: 'urn:xmpp:jingle:1',
-            action: 'source-remove',
-            initiator: self.initiator,
-            sid: self.sid
+            action: 'source-add',
+            initiator: this.initiator,
+            sid: this.sid
         }
     );
-    var removed = sdpDiffer.toJingle(remove);
-    if (removed) {
-        this.connection.sendIQ(remove,
+    var added = sdpDiffer.toJingle(add);
+    if (added) {
+        this.connection.sendIQ(add,
             function (res) {
-                console.info('got remove result', res);
+                console.info('got add result', res);
             },
             function (err) {
-                console.error('got remove error', err);
+                console.error('got add error', err);
             }
         );
     } else {
-        console.log('removal not necessary');
+        console.log('addition not necessary');
     }
 };